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base: mediocregopher:2be865181d0cedc66e8c7f9eae7f98db8152d56c
Branches Tags
mediocregopher:master
mediocregopher:rust
mediocregopher:viewRender
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compare: mediocregopher:487045543098885d15366a5449829944367658a5
Branches Tags
mediocregopher:master
mediocregopher:rust
mediocregopher:viewRender

3 Commits
2be865181d ... 4870455430

Author SHA1 Message Date
Brian Picciano
4870455430 Completely refactor gg with new BNF file and decoder 
The new gg format is based on a BNF file which can be found in the `gg`
directory. The code for decoding `.gg` files has been refactored to
mirror that file. The result is more resilient parsing, better errors,
and a greater ability to extend the format in the future.

The new decoder is notable in that it does not use a lexer. Both lexing
and parsing are done in a single step.

The format syntax itself has also been modified. Rather than using
semi-colons everywhere, commas are used as separators in tuples.
Additionally the final comma/semi-colon is no longer required.
 2023-10-25 11:31:33 +02:00
Brian Picciano
21c91731e9 Rename Operation to Function, plus some cleanup 2023-10-16 18:20:01 +02:00
Brian Picciano
7d0fcbf28a Switch to using nix flakes, and update go to a real version 2023-10-16 18:16:17 +02:00
25 changed files with 1398 additions and 1339 deletions
Show Stats Expand all files Collapse all files

10
README.md
View File

@ -6,18 +6,16 @@ super-early-alpha-don't-actually-use-this-for-anything development.
## Development ## Development
Current efforts on ginger are focused on a golang-based virtual machine, which Current efforts on ginger are focused on a golang-based virtual machine, which
will then be used to bootstrap the language. go >=1.18 is required for this vm. will then be used to bootstrap the language.
If you are on a linux-amd64 machine with nix installed, you can run: If you are on a machine with nix installed, you can run:
``` ```
nix-shell -A shell nix develop
``` ```
from the repo root and you will be dropped into a shell with all dependencies from the repo root and you will be dropped into a shell with all dependencies
(including the correct go version) in your PATH, ready to use. This could (including the correct go version) in your PATH, ready to use.
probably be expanded to other OSs/architectures easily, if you care to do so
please check out the `default.nix` file and submit a PR!
## Demo ## Demo

6
cmd/eval/main.go
View File

@ -19,10 +19,7 @@ func main() {
opSrc := os.Args[1] opSrc := os.Args[1]
inSrc := os.Args[2] inSrc := os.Args[2]
inVal, err := gg.DecodeSingleValueFromLexer( inVal, err := gg.NewDecoder(bytes.NewBufferString(inSrc)).Next()
gg.NewLexer(bytes.NewBufferString(inSrc + ";")),
)
if err != nil { if err != nil {
panic(fmt.Sprintf("decoding input: %v", err)) panic(fmt.Sprintf("decoding input: %v", err))
} }
@ -32,7 +29,6 @@ func main() {
vm.Value{Value: inVal}, vm.Value{Value: inVal},
vm.GlobalScope, vm.GlobalScope,
) )
if err != nil { if err != nil {
panic(fmt.Sprintf("evaluating: %v", err)) panic(fmt.Sprintf("evaluating: %v", err))
} }

25
default.nix
View File

@ -1,25 +0,0 @@
{
pkgs ? import (fetchTarball {
name = "nixpkgs-21-11";
url = "https://github.com/NixOS/nixpkgs/archive/a7ecde854aee5c4c7cd6177f54a99d2c1ff28a31.tar.gz";
sha256 = "162dywda2dvfj1248afxc45kcrg83appjd0nmdb541hl7rnncf02";
}) { },
}: rec {
# https://go.dev/dl/#go1.18beta1
go = fetchTarball {
name = "go1.18beta1";
url = "https://go.dev/dl/go1.18beta1.linux-amd64.tar.gz";
sha256 = "09sb0viv1ybx6adgx4jym1sckdq3mpjkd6albj06hwnchj5rqn40";
};
shell = pkgs.mkShell {
name = "ginger-dev";
buildInputs = [
go
];
};
}

33
examples/fib.gg
View File

@ -1,19 +1,24 @@
out = { * A function which accepts a number N and returns the Nth fibonacci number
{
* We are passing a tuple of inputs into a graph here, such that the graph is
* evaluated as an anonymous function. That anonymous function uses recur
* internally to compute the result.
out = {
decr = { out = add < (in; -1;); }; * A little helper function.
decr = { out = add < (in, -1) };
n = tupEl < (in; 0;); * Deconstruct the input tuple into its individual elements, for clarity.
a = tupEl < (in; 1;); * There will be a more ergonomic way of doing this one day.
b = tupEl < (in; 2;); n = tupEl < (in, 0);
a = tupEl < (in, 1);
b = tupEl < (in, 2);
out = if < ( out = if < (
isZero < n; isZero < n,
a; a,
recur < ( recur < ( decr<n, b, add<(a,b) ),
decr < n;
b;
add < (a;b;);
); );
);
} < (in; 0; 1;); } < (in, 0, 1);
}

26
flake.lock Normal file
View File

@ -0,0 +1,26 @@
{
"nodes": {
"nixpkgs": {
"locked": {
"lastModified": 1696983906,
"narHash": "sha256-L7GyeErguS7Pg4h8nK0wGlcUTbfUMDu+HMf1UcyP72k=",
"owner": "NixOS",
"repo": "nixpkgs",
"rev": "bd1cde45c77891214131cbbea5b1203e485a9d51",
"type": "github"
},
"original": {
"id": "nixpkgs",
"ref": "nixos-23.05",
"type": "indirect"
}
},
"root": {
"inputs": {
"nixpkgs": "nixpkgs"
}
}
},
"root": "root",
"version": 7
}

44
flake.nix Normal file
View File

@ -0,0 +1,44 @@
{
description = "gotc development environment";
# Nixpkgs / NixOS version to use.
inputs.nixpkgs.url = "nixpkgs/nixos-23.05";
outputs = { self, nixpkgs }:
let
# to work with older version of flakes
lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";
# Generate a user-friendly version number.
version = builtins.substring 0 8 lastModifiedDate;
# System types to support.
supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];
# Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
# Nixpkgs instantiated for supported system types.
nixpkgsFor = forAllSystems (system: import nixpkgs {
inherit system;
});
in
{
# Add dependencies that are only needed for development
devShells = forAllSystems (system:
let
pkgs = nixpkgsFor.${system};
in {
default = pkgs.mkShell {
buildInputs = [
pkgs.go
pkgs.gotools
pkgs.golangci-lint
];
};
});
};
}

362
gg/decoder.go
View File

@ -1,353 +1,73 @@
package gg package gg
import ( import (
"errors" "bufio"
"fmt" "fmt"
"io" "io"
"strconv"
"github.com/mediocregopher/ginger/graph"
) )
// Type aliases for convenience // Decoder reads Value's off of a byte stream.
type ( type Decoder struct {
Graph = graph.Graph[Value, Value] br *bufio.Reader
OpenEdge = graph.OpenEdge[Value, Value] brNextLoc Location
)
// Punctuations which are used in the gg file format. unread []locatableRune
const ( lastRead locatableRune
punctTerm = ";"
punctOp = "<"
punctAssign = "="
punctOpenGraph = "{"
punctCloseGraph = "}"
punctOpenTuple = "("
punctCloseTuple = ")"
)
func decoderErr(tok LexerToken, err error) error {
return fmt.Errorf("%s: %w", tok.errPrefix(), err)
} }
func decoderErrf(tok LexerToken, str string, args ...interface{}) error { // NewDecoder returns a Decoder which will decode the given stream as a gg
return decoderErr(tok, fmt.Errorf(str, args...)) // formatted stream of a Values.
} func NewDecoder(r io.Reader) *Decoder {
return &Decoder{
func isPunct(tok LexerToken, val string) bool { br: bufio.NewReader(r),
return tok.Kind == LexerTokenKindPunctuation && tok.Value == val brNextLoc: Location{Row: 1, Col: 1},
}
func isTerm(tok LexerToken) bool {
return isPunct(tok, punctTerm)
}
// decoder is currently only really used to namespace functions related to
// decoding Graphs. It may later have actual fields added to it, such as for
// options passed by the caller.
type decoder struct{}
// returned boolean value indicates if the token following the single token is a
// term. If a term followed the first token then it is not included in the
// returned leftover tokens.
//
// if termed is false then leftover tokens cannot be empty.
func (d *decoder) parseSingleValue(
toks []LexerToken,
) (
Value, []LexerToken, bool, error,
) {
tok, rest := toks[0], toks[1:]
if len(rest) == 0 {
return ZeroValue, nil, false, decoderErrf(tok, "cannot be final token, possibly missing %q", punctTerm)
}
termed := isTerm(rest[0])
if termed {
rest = rest[1:]
}
switch tok.Kind {
case LexerTokenKindName:
return Value{Name: &tok.Value, LexerToken: &tok}, rest, termed, nil
case LexerTokenKindNumber:
i, err := strconv.ParseInt(tok.Value, 10, 64)
if err != nil {
return ZeroValue, nil, false, decoderErrf(tok, "parsing %q as integer: %w", tok.Value, err)
}
return Value{Number: &i, LexerToken: &tok}, rest, termed, nil
case LexerTokenKindPunctuation:
return ZeroValue, nil, false, decoderErrf(tok, "expected value, found punctuation %q", tok.Value)
default:
panic(fmt.Sprintf("unexpected token kind %q", tok.Kind))
} }
} }
func (d *decoder) parseOpenEdge( func (d *Decoder) readRune() (locatableRune, error) {
toks []LexerToken, if len(d.unread) > 0 {
) ( d.lastRead = d.unread[len(d.unread)-1]
*OpenEdge, []LexerToken, error, d.unread = d.unread[:len(d.unread)-1]
) { return d.lastRead, nil
if isPunct(toks[0], punctOpenTuple) {
return d.parseTuple(toks)
} }
var ( loc := d.brNextLoc
val Value
termed bool
err error
)
switch {
case isPunct(toks[0], punctOpenGraph):
val, toks, termed, err = d.parseGraphValue(toks, true)
default:
val, toks, termed, err = d.parseSingleValue(toks)
}
r, _, err := d.br.ReadRune()
if err != nil { if err != nil {
return nil, nil, err return d.lastRead, err
} }
if termed { if r == '\n' {
return graph.ValueOut[Value](ZeroValue, val), toks, nil d.brNextLoc.Row++
d.brNextLoc.Col = 1
} else {
d.brNextLoc.Col++
} }
opTok, toks := toks[0], toks[1:] d.lastRead = locatableRune{loc, r}
return d.lastRead, nil
if !isPunct(opTok, punctOp) {
return nil, nil, decoderErrf(opTok, "must be %q or %q", punctOp, punctTerm)
}
if len(toks) == 0 {
return nil, nil, decoderErrf(opTok, "%q cannot terminate an edge declaration", punctOp)
}
oe, toks, err := d.parseOpenEdge(toks)
if err != nil {
return nil, nil, err
}
oe = graph.TupleOut[Value](val, oe)
return oe, toks, nil
} }
func (d *decoder) parseTuple( func (d *Decoder) unreadRune(lr locatableRune) {
toks []LexerToken, if d.lastRead != lr {
) ( panic(fmt.Sprintf(
*OpenEdge, []LexerToken, error, "unreading rune %#v, but last read rune was %#v", lr, d.lastRead,
) { ))
openTok, toks := toks[0], toks[1:]
var edges []*OpenEdge
for {
if len(toks) == 0 {
return nil, nil, decoderErrf(openTok, "no matching %q", punctCloseTuple)
} else if isPunct(toks[0], punctCloseTuple) {
toks = toks[1:]
break
}
var (
oe *OpenEdge
err error
)
oe, toks, err = d.parseOpenEdge(toks)
if err != nil {
return nil, nil, err
}
edges = append(edges, oe)
} }
// this is a quirk of the syntax, _technically_ a tuple doesn't need a d.unread = append(d.unread, lr)
// term after it, since it can't be used as an edge value, and so
// nothing can come after it in the chain.
if len(toks) > 0 && isTerm(toks[0]) {
toks = toks[1:]
}
return graph.TupleOut[Value](ZeroValue, edges...), toks, nil
} }
// returned boolean value indicates if the token following the graph is a term. func (d *Decoder) nextLoc() Location {
// If a term followed the first token then it is not included in the returned if len(d.unread) > 0 {
// leftover tokens. return d.unread[len(d.unread)-1].Location
//
// if termed is false then leftover tokens cannot be empty.
func (d *decoder) parseGraphValue(
toks []LexerToken, expectWrappers bool,
) (
Value, []LexerToken, bool, error,
) {
var openTok LexerToken
if expectWrappers {
openTok, toks = toks[0], toks[1:]
} }
g := new(Graph) return d.brNextLoc
for {
if len(toks) == 0 {
if !expectWrappers {
break
}
return ZeroValue, nil, false, decoderErrf(openTok, "no matching %q", punctCloseGraph)
} else if closingTok := toks[0]; isPunct(closingTok, punctCloseGraph) {
if !expectWrappers {
return ZeroValue, nil, false, decoderErrf(closingTok, "unexpected %q", punctCloseGraph)
}
toks = toks[1:]
if len(toks) == 0 {
return ZeroValue, nil, false, decoderErrf(closingTok, "cannot be final token, possibly missing %q", punctTerm)
}
break
}
var err error
if g, toks, err = d.parseValIn(g, toks); err != nil {
return ZeroValue, nil, false, err
}
}
val := Value{Graph: g}
if !expectWrappers {
return val, toks, true, nil
}
val.LexerToken = &openTok
termed := isTerm(toks[0])
if termed {
toks = toks[1:]
}
return val, toks, termed, nil
} }
func (d *decoder) parseValIn(into *Graph, toks []LexerToken) (*Graph, []LexerToken, error) { // Next returns the next top-level value in the stream, or io.EOF.
func (d *Decoder) Next() (Value, error) {
if len(toks) == 0 { return topLevelTerm.decodeFn(d)
return into, nil, nil
} else if len(toks) < 3 {
return nil, nil, decoderErrf(toks[0], `must be of the form "<name> = ..."`)
}
dst := toks[0]
eq := toks[1]
toks = toks[2:]
if dst.Kind != LexerTokenKindName {
return nil, nil, decoderErrf(dst, "must be a name")
} else if !isPunct(eq, punctAssign) {
return nil, nil, decoderErrf(eq, "must be %q", punctAssign)
}
oe, toks, err := d.parseOpenEdge(toks)
if err != nil {
return nil, nil, err
}
dstVal := Value{Name: &dst.Value, LexerToken: &dst}
return into.AddValueIn(dstVal, oe), toks, nil
}
func (d *decoder) readAllTokens(lexer Lexer) ([]LexerToken, error) {
var toks []LexerToken
for {
tok, err := lexer.Next()
if errors.Is(err, io.EOF) {
break
} else if err != nil {
return nil, fmt.Errorf("reading next token: %w", err)
}
toks = append(toks, tok)
}
return toks, nil
}
func (d *decoder) decode(lexer Lexer) (*Graph, error) {
toks, err := d.readAllTokens(lexer)
if err != nil {
return nil, err
}
val, _, _, err := d.parseGraphValue(toks, false)
if err != nil {
return nil, err
}
return val.Graph, nil
}
// DecodeLexer reads lexigraphical tokens from the given Lexer and uses them to
// construct a Graph according to the rules of the gg file format. DecodeLexer
// will only return an error if there is a non-EOF file returned from the Lexer,
// or the tokens read cannot be used to construct a valid Graph.
func DecodeLexer(lexer Lexer) (*Graph, error) {
decoder := &decoder{}
return decoder.decode(lexer)
}
func DecodeSingleValueFromLexer(lexer Lexer) (Value, error) {
decoder := &decoder{}
toks, err := decoder.readAllTokens(lexer)
if err != nil {
return ZeroValue, err
}
val, _, _, err := decoder.parseSingleValue(toks)
return val, err
} }

149
gg/decoder_test.go
View File

@ -1,149 +0,0 @@
package gg
import (
"strconv"
"testing"
"github.com/stretchr/testify/assert"
"github.com/mediocregopher/ginger/graph"
)
func TestDecoder(t *testing.T) {
zeroGraph := new(Graph)
i := func(i int64) Value {
return Value{Number: &i}
}
n := func(n string) Value {
return Value{Name: &n}
}
vOut := func(edgeVal, val Value) *OpenEdge {
return graph.ValueOut(edgeVal, val)
}
tOut := func(edgeVal Value, ins ...*OpenEdge) *OpenEdge {
return graph.TupleOut(edgeVal, ins...)
}
tests := []struct {
in string
exp *Graph
}{
{
in: "",
exp: zeroGraph,
},
{
in: "out = 1;",
exp: zeroGraph.AddValueIn(n("out"), vOut(ZeroValue, i(1))),
},
{
in: "out = incr < 1;",
exp: zeroGraph.AddValueIn(n("out"), vOut(n("incr"), i(1))),
},
{
in: "out = a < b < 1;",
exp: zeroGraph.AddValueIn(
n("out"),
tOut(
n("a"),
vOut(n("b"),
i(1)),
),
),
},
{
in: "out = a < b < (1; c < 2; d < e < 3;);",
exp: zeroGraph.AddValueIn(
n("out"),
tOut(
n("a"),
tOut(
n("b"),
vOut(ZeroValue, i(1)),
vOut(n("c"), i(2)),
tOut(
n("d"),
vOut(n("e"), i(3)),
),
),
),
),
},
{
in: "out = a < b < (1; c < (d < 2; 3;); );",
exp: zeroGraph.AddValueIn(
n("out"),
tOut(
n("a"),
tOut(
n("b"),
vOut(ZeroValue, i(1)),
tOut(
n("c"),
vOut(n("d"), i(2)),
vOut(ZeroValue, i(3)),
),
),
),
),
},
{
in: "out = { a = 1; b = c < d < 2; };",
exp: zeroGraph.AddValueIn(
n("out"),
vOut(
ZeroValue,
Value{Graph: zeroGraph.
AddValueIn(n("a"), vOut(ZeroValue, i(1))).
AddValueIn(
n("b"),
tOut(
n("c"),
vOut(n("d"), i(2)),
),
),
},
),
),
},
{
in: "out = a < { b = 1; } < 2;",
exp: zeroGraph.AddValueIn(
n("out"),
tOut(
n("a"),
vOut(
Value{Graph: zeroGraph.
AddValueIn(n("b"), vOut(ZeroValue, i(1))),
},
i(2),
),
),
),
},
{
in: "a = 1; b = 2;",
exp: zeroGraph.
AddValueIn(n("a"), vOut(ZeroValue, i(1))).
AddValueIn(n("b"), vOut(ZeroValue, i(2))),
},
}
for i, test := range tests {
t.Run(strconv.Itoa(i), func(t *testing.T) {
r := &mockReader{body: []byte(test.in)}
lexer := NewLexer(r)
got, err := DecodeLexer(lexer)
assert.NoError(t, err)
assert.True(t, got.Equal(test.exp), "\nexp:%v\ngot:%v", test.exp, got)
})
}
}

23
gg/gg.bnf Normal file
View File

@ -0,0 +1,23 @@
<digit> ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
<positive-number> ::= <digit>+
<negative-number> ::= "-" <positive-number>
<number> ::= <negative-number> | <positive-number>
<name> ::= (<letter> | <mark>) (<letter> | <mark> | <digit>)*
<tuple> ::= "(" <tuple-tail>
<tuple-tail> ::= ")" | <tuple-open-edge>
<tuple-open-edge> ::= <value> <tuple-open-edge-value-tail>
| <tuple> <tuple-open-edge-tail>
<tuple-open-edge-tail> ::= ")" | "," <tuple-tail>
<tuple-open-edge-value-tail> ::= <tuple-open-edge-tail> | "<" <tuple-open-edge>
<graph> ::= "{" <graph-tail>
<graph-tail> ::= "}" | <name> "=" <graph-open-edge>
<graph-open-edge> ::= <value> <graph-open-edge-value-tail>
| <tuple> <graph-open-edge-tail>
<graph-open-edge-tail> ::= "}" | ";" <graph-tail>
<graph-open-edge-value-tail> ::= <graph-open-edge-tail> | "<" <graph-open-edge>
<value> ::= <name> | <number> | <graph>
<gg> ::= <eof> | <value> <gg>

68
gg/gg.go
View File

@ -7,23 +7,20 @@ import (
"github.com/mediocregopher/ginger/graph" "github.com/mediocregopher/ginger/graph"
) )
// ZeroValue is a Value with no fields set. // Type aliases for convenience
var ZeroValue Value type (
Graph = graph.Graph[OptionalValue, Value]
OpenEdge = graph.OpenEdge[OptionalValue, Value]
)
// Value represents a value which can be serialized by the gg text format. // Value represents a value which can be serialized by the gg text format.
type Value struct { type Value struct {
Location
// Only one of these fields may be set // Only one of these fields may be set
Name *string Name *string
Number *int64 Number *int64
Graph *Graph Graph *Graph
// TODO coming soon!
// String *string
// Optional fields indicating the token which was used to construct this
// Value, if any.
LexerToken *LexerToken
} }
// Name returns a name Value. // Name returns a name Value.
@ -36,12 +33,6 @@ func Number(n int64) Value {
return Value{Number: &n} return Value{Number: &n}
} }
// IsZero returns true if the Value is the zero value (none of the sub-value
// fields are set). LexerToken is ignored for this check.
func (v Value) IsZero() bool {
return v.Equal(ZeroValue)
}
// Equal returns true if the passed in Value is equivalent, ignoring the // Equal returns true if the passed in Value is equivalent, ignoring the
// LexerToken on either Value. // LexerToken on either Value.
// //
@ -50,13 +41,8 @@ func (v Value) Equal(v2g graph.Value) bool {
v2 := v2g.(Value) v2 := v2g.(Value)
v.LexerToken, v2.LexerToken = nil, nil
switch { switch {
case v == ZeroValue && v2 == ZeroValue:
return true
case v.Name != nil && v2.Name != nil && *v.Name == *v2.Name: case v.Name != nil && v2.Name != nil && *v.Name == *v2.Name:
return true return true
@ -85,6 +71,46 @@ func (v Value) String() string {
return v.Graph.String() return v.Graph.String()
default: default:
return "<zero>" panic("no fields set on Value")
} }
} }
// OptionalValue is a Value which may be unset. This is used for edge values,
// since edges might not have a value.
type OptionalValue struct {
Value
Valid bool
}
// None is the zero OptionalValue (hello rustaceans).
var None OptionalValue
// Some wraps a Value to be an OptionalValue.
func Some(v Value) OptionalValue {
return OptionalValue{Valid: true, Value: v}
}
func (v OptionalValue) String() string {
if !v.Valid {
return "<none>"
}
return v.Value.String()
}
func (v OptionalValue) Equal(v2g graph.Value) bool {
var v2 OptionalValue
if v2Val, ok := v2g.(Value); ok {
v2 = Some(v2Val)
} else {
v2 = v2g.(OptionalValue)
}
if v.Valid != v2.Valid {
return false
} else if !v.Valid {
return true
}
return v.Value.Equal(v2.Value)
}

292
gg/lexer.go
View File

@ -1,292 +0,0 @@
package gg
import (
"bufio"
"fmt"
"io"
"strings"
"unicode"
)
// LexerLocation describes the location in a file where a particular token was
// parsed from.
type LexerLocation struct {
Row, Col int
}
func (l LexerLocation) String() string {
return fmt.Sprintf("%d:%d", l.Row, l.Col)
}
// LexerError is returned by Lexer when an unexpected error occurs parsing a
// stream of LexerTokens.
type LexerError struct {
Err error
Location LexerLocation
}
func (e *LexerError) Error() string {
return fmt.Sprintf("%s: %s", e.Location.String(), e.Err.Error())
}
func (e *LexerError) Unwrap() error {
return e.Err
}
// LexerTokenKind enumerates the different kinds of LexerToken there can be.
type LexerTokenKind string
// Enumeration of LexerTokenKinds.
const (
LexerTokenKindName LexerTokenKind = "name"
LexerTokenKindNumber LexerTokenKind = "number"
LexerTokenKindPunctuation LexerTokenKind = "punctuation"
)
// LexerToken describes a lexigraphical token which is used when deserializing
// Graphs.
type LexerToken struct {
Kind LexerTokenKind
Value string // never empty string
Location LexerLocation
}
func (t LexerToken) errPrefix() string {
return fmt.Sprintf("%s: at %q", t.Location.String(), t.Value)
}
// Lexer is used to parse a string stream into a sequence of tokens which can
// then be parsed by a Parser.
type Lexer interface {
// Next will return a LexerToken or a LexerError. io.EOF (wrapped in a
// LexerError) is returned if the stream being read from is finished.
Next() (LexerToken, error)
}
type lexer struct {
r *bufio.Reader
stringBuilder *strings.Builder
err *LexerError
// these fields are only needed to keep track of the current "cursor"
// position when reading.
lastRow, lastCol int
prevRune rune
}
// NewLexer wraps the io.Reader in a Lexer, which will read the io.Reader as a
// sequence of utf-8 characters and parse it into a sequence of LexerTokens.
func NewLexer(r io.Reader) Lexer {
return &lexer{
r: bufio.NewReader(r),
lastRow: 0,
lastCol: -1,
stringBuilder: new(strings.Builder),
}
}
// nextRowCol returns the row and column number which the next rune in the
// stream would be at.
func (l *lexer) nextRowCol() (int, int) {
if l.prevRune == '\n' {
return l.lastRow + 1, 0
}
return l.lastRow, l.lastCol + 1
}
func (l *lexer) fmtErr(err error) *LexerError {
row, col := l.nextRowCol()
return &LexerError{
Err: err,
Location: LexerLocation{
Row: row,
Col: col,
},
}
}
func (l *lexer) fmtErrf(str string, args ...interface{}) *LexerError {
return l.fmtErr(fmt.Errorf(str, args...))
}
// discardRune must _always_ be called only after peekRune.
func (l *lexer) discardRune() {
r, _, err := l.r.ReadRune()
if err != nil {
panic(err)
}
l.lastRow, l.lastCol = l.nextRowCol()
l.prevRune = r
}
func (l *lexer) peekRune() (rune, error) {
r, _, err := l.r.ReadRune()
if err != nil {
return '0', err
} else if err := l.r.UnreadRune(); err != nil {
// since the most recent operation on the bufio.Reader was a ReadRune,
// UnreadRune should never return an error
panic(err)
}
return r, nil
}
// readWhile reads runes until the given predicate returns false, and returns a
// LexerToken of the given kind whose Value is comprised of all runes which
// returned true.
//
// If an error is encountered then both the token (or what's been parsed of it
// so far) and the error are returned.
func (l *lexer) readWhile(
kind LexerTokenKind, pred func(rune) bool,
) (
LexerToken, *LexerError,
) {
row, col := l.nextRowCol()
l.stringBuilder.Reset()
var lexErr *LexerError
for {
r, err := l.peekRune()
if err != nil {
lexErr = l.fmtErrf("peeking next character: %w", err)
break
} else if !pred(r) {
break
}
l.stringBuilder.WriteRune(r)
l.discardRune()
}
return LexerToken{
Kind: kind,
Value: l.stringBuilder.String(),
Location: LexerLocation{
Row: row, Col: col,
},
}, lexErr
}
// we only support base-10 integers at the moment.
func isNumber(r rune) bool {
return r == '-' || ('0' <= r && r <= '9')
}
// next can return a token, an error, or both. If an error is returned then no
// further calls to next should occur.
func (l *lexer) next() (LexerToken, *LexerError) {
for {
r, err := l.peekRune()
if err != nil {
return LexerToken{}, l.fmtErrf("peeking next character: %w", err)
}
switch {
case r == '*': // comment
// comments are everything up until a newline
_, err := l.readWhile("", func(r rune) bool {
return r != '\n'
})
if err != nil {
return LexerToken{}, err
}
// terminating newline will be discarded on next loop
case r == '"' || r == '`':
// reserve double-quote and backtick for string parsing.
l.discardRune()
return LexerToken{}, l.fmtErrf("string parsing not yet implemented")
case unicode.IsLetter(r):
// letters denote the start of a name
return l.readWhile(LexerTokenKindName, func(r rune) bool {
if unicode.In(r, unicode.Letter, unicode.Number, unicode.Mark) {
return true
}
if r == '-' {
return true
}
return false
})
case isNumber(r):
return l.readWhile(LexerTokenKindNumber, isNumber)
case unicode.IsPunct(r) || unicode.IsSymbol(r):
// symbols are also considered punctuation
l.discardRune()
return LexerToken{
Kind: LexerTokenKindPunctuation,
Value: string(r),
Location: LexerLocation{
Row: l.lastRow,
Col: l.lastCol,
},
}, nil
case unicode.IsSpace(r):
l.discardRune()
default:
return LexerToken{}, l.fmtErrf("unexpected character %q", r)
}
}
}
func (l *lexer) Next() (LexerToken, error) {
if l.err != nil {
return LexerToken{}, l.err
}
tok, err := l.next()
if err != nil {
l.err = err
if tok.Kind == "" {
return LexerToken{}, l.err
}
}
return tok, nil
}

150
gg/lexer_test.go
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@ -1,150 +0,0 @@
package gg
import (
"errors"
"strconv"
"strings"
"testing"
"github.com/stretchr/testify/assert"
)
func TestLexer(t *testing.T) {
expErr := errors.New("eof")
tests := []struct {
in string
exp []LexerToken
}{
{in: "", exp: []LexerToken{}},
{in: "* fooo\n", exp: []LexerToken{}},
{
in: "foo",
exp: []LexerToken{
{
Kind: LexerTokenKindName,
Value: "foo",
Location: LexerLocation{Row: 0, Col: 0},
},
},
},
{
in: "foo bar\nf-o f0O Foo",
exp: []LexerToken{
{
Kind: LexerTokenKindName,
Value: "foo",
Location: LexerLocation{Row: 0, Col: 0},
},
{
Kind: LexerTokenKindName,
Value: "bar",
Location: LexerLocation{Row: 0, Col: 4},
},
{
Kind: LexerTokenKindName,
Value: "f-o",
Location: LexerLocation{Row: 1, Col: 0},
},
{
Kind: LexerTokenKindName,
Value: "f0O",
Location: LexerLocation{Row: 1, Col: 4},
},
{
Kind: LexerTokenKindName,
Value: "Foo",
Location: LexerLocation{Row: 1, Col: 8},
},
},
},
{
in: "1 100 -100",
exp: []LexerToken{
{
Kind: LexerTokenKindNumber,
Value: "1",
Location: LexerLocation{Row: 0, Col: 0},
},
{
Kind: LexerTokenKindNumber,
Value: "100",
Location: LexerLocation{Row: 0, Col: 2},
},
{
Kind: LexerTokenKindNumber,
Value: "-100",
Location: LexerLocation{Row: 0, Col: 6},
},
},
},
{
in: "1<2!-3 ()",
exp: []LexerToken{
{
Kind: LexerTokenKindNumber,
Value: "1",
Location: LexerLocation{Row: 0, Col: 0},
},
{
Kind: LexerTokenKindPunctuation,
Value: "<",
Location: LexerLocation{Row: 0, Col: 1},
},
{
Kind: LexerTokenKindNumber,
Value: "2",
Location: LexerLocation{Row: 0, Col: 2},
},
{
Kind: LexerTokenKindPunctuation,
Value: "!",
Location: LexerLocation{Row: 0, Col: 3},
},
{
Kind: LexerTokenKindNumber,
Value: "-3",
Location: LexerLocation{Row: 0, Col: 4},
},
{
Kind: LexerTokenKindPunctuation,
Value: "(",
Location: LexerLocation{Row: 0, Col: 7},
},
{
Kind: LexerTokenKindPunctuation,
Value: ")",
Location: LexerLocation{Row: 0, Col: 8},
},
},
},
}
for i, test := range tests {
t.Run(strconv.Itoa(i), func(t *testing.T) {
lexer := NewLexer(&mockReader{body: []byte(test.in), err: expErr})
for i := range test.exp {
tok, err := lexer.Next()
assert.NoError(t, err)
assert.Equal(t, test.exp[i], tok, "test.exp[%d]", i)
}
tok, err := lexer.Next()
assert.ErrorIs(t, err, expErr)
assert.Equal(t, LexerToken{}, tok)
lexErr := new(LexerError)
assert.True(t, errors.As(err, &lexErr))
inParts := strings.Split(test.in, "\n")
assert.ErrorIs(t, lexErr, expErr)
assert.Equal(t, lexErr.Location.Row, len(inParts)-1)
assert.Equal(t, lexErr.Location.Col, len(inParts[len(inParts)-1]))
})
}
}

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package gg
import "fmt"
// Location indicates a position in a stream of bytes identified by column
// within newline-separated rows.
type Location struct {
Row, Col int
}
func (l Location) errf(str string, args ...any) LocatedError {
return LocatedError{l, fmt.Errorf(str, args...)}
}
func (l Location) locate() Location { return l }
// LocatedError is an error related to a specific point within a decode gg
// stream.
type LocatedError struct {
Location
Err error
}
func (e LocatedError) Error() string {
return fmt.Sprintf("%d:%d: %v", e.Row, e.Col, e.Err)
}
type locatableRune struct {
Location
r rune
}
type locatableString struct {
Location
str string
}

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package gg
import (
"errors"
"fmt"
"io"
"strconv"
"strings"
"unicode"
"github.com/mediocregopher/ginger/graph"
"golang.org/x/exp/slices"
)
var (
errNoMatch = errors.New("not found")
)
type stringerFn func() string
func (fn stringerFn) String() string {
return fn()
}
type stringerStr string
func (str stringerStr) String() string {
return string(str)
}
type term[T any] struct {
name fmt.Stringer
decodeFn func(d *Decoder) (T, error)
}
func (t term[T]) String() string {
return t.name.String()
}
func firstOf[T any](terms ...*term[T]) *term[T] {
if len(terms) < 2 {
panic("firstOfTerms requires at least 2 terms")
}
return &term[T]{
name: stringerFn(func() string {
descrs := make([]string, len(terms))
for i := range terms {
descrs[i] = terms[i].String()
}
return strings.Join(descrs, " or ")
}),
decodeFn: func(d *Decoder) (T, error) {
var zero T
for _, t := range terms {
v, err := t.decodeFn(d)
if errors.Is(err, errNoMatch) {
continue
} else if err != nil {
return zero, err
}
return v, nil
}
return zero, errNoMatch
},
}
}
func seq[Ta, Tb, Tc any](
name fmt.Stringer,
termA *term[Ta],
termB *term[Tb],
fn func(Ta, Tb) Tc,
) *term[Tc] {
return &term[Tc]{
name: name,
decodeFn: func(d *Decoder) (Tc, error) {
var zero Tc
va, err := termA.decodeFn(d)
if err != nil {
return zero, err
}
vb, err := termB.decodeFn(d)
if errors.Is(err, errNoMatch) {
return zero, d.nextLoc().errf("expected %v", termB)
} else if err != nil {
return zero, err
}
return fn(va, vb), nil
},
}
}
func prefixed[Ta, Tb any](termA *term[Ta], termB *term[Tb]) *term[Tb] {
return seq(termA, termA, termB, func(_ Ta, b Tb) Tb {
return b
})
}
func prefixIgnored[Ta, Tb any](termA *term[Ta], termB *term[Tb]) *term[Tb] {
return &term[Tb]{
name: termB,
decodeFn: func(d *Decoder) (Tb, error) {
var zero Tb
if _, err := termA.decodeFn(d); err != nil {
return zero, err
}
return termB.decodeFn(d)
},
}
}
func suffixIgnored[Ta, Tb any](
termA *term[Ta], termB *term[Tb],
) *term[Ta] {
return seq(termA, termA, termB, func(a Ta, _ Tb) Ta {
return a
})
}
func oneOrMore[T any](t *term[T]) *term[[]T] {
return &term[[]T]{
name: stringerFn(func() string {
return fmt.Sprintf("one or more %v", t)
}),
decodeFn: func(d *Decoder) ([]T, error) {
var vv []T
for {
v, err := t.decodeFn(d)
if errors.Is(err, errNoMatch) {
break
} else if err != nil {
return nil, err
}
vv = append(vv, v)
}
if len(vv) == 0 {
return nil, errNoMatch
}
return vv, nil
},
}
}
func zeroOrMore[T any](t *term[T]) *term[[]T] {
return &term[[]T]{
name: stringerFn(func() string {
return fmt.Sprintf("zero or more %v", t)
}),
decodeFn: func(d *Decoder) ([]T, error) {
var vv []T
for {
v, err := t.decodeFn(d)
if errors.Is(err, errNoMatch) {
break
} else if err != nil {
return nil, err
}
vv = append(vv, v)
}
return vv, nil
},
}
}
func mapTerm[Ta, Tb any](
name fmt.Stringer, t *term[Ta], fn func(Ta) Tb,
) *term[Tb] {
return &term[Tb]{
name: name,
decodeFn: func(d *Decoder) (Tb, error) {
var zero Tb
va, err := t.decodeFn(d)
if err != nil {
return zero, err
}
return fn(va), nil
},
}
}
func runePredTerm(
name fmt.Stringer, pred func(rune) bool,
) *term[locatableRune] {
return &term[locatableRune]{
name: name,
decodeFn: func(d *Decoder) (locatableRune, error) {
lr, err := d.readRune()
if errors.Is(err, io.EOF) {
return locatableRune{}, errNoMatch
} else if err != nil {
return locatableRune{}, err
}
if !pred(lr.r) {
d.unreadRune(lr)
return locatableRune{}, errNoMatch
}
return lr, nil
},
}
}
func runeTerm(r rune) *term[locatableRune] {
return runePredTerm(
stringerStr(fmt.Sprintf("'%c'", r)),
func(r2 rune) bool { return r2 == r },
)
}
func locatableRunesToString(rr []locatableRune) string {
str := make([]rune, len(rr))
for i := range rr {
str[i] = rr[i].r
}
return string(str)
}
func runesToStringTerm(
t *term[[]locatableRune],
) *term[locatableString] {
return mapTerm(
t, t, func(rr []locatableRune) locatableString {
return locatableString{rr[0].locate(), locatableRunesToString(rr)}
},
)
}
func discard[T any](t *term[T]) *term[struct{}] {
return mapTerm(t, t, func(_ T) struct{} { return struct{}{} })
}
var (
notNewlineTerm = runePredTerm(
stringerStr("not-newline"),
func(r rune) bool { return r != '\n' },
)
commentTerm = prefixed(
prefixed(runeTerm('*'), zeroOrMore(notNewlineTerm)),
runeTerm('\n'),
)
whitespaceTerm = zeroOrMore(firstOf(
discard(runePredTerm(stringerStr("whitespace"), unicode.IsSpace)),
discard(commentTerm),
))
)
func trimmedTerm[T any](t *term[T]) *term[T] {
t = prefixIgnored(whitespaceTerm, t)
t = suffixIgnored(t, whitespaceTerm)
return t
}
func trimmedRuneTerm(r rune) *term[locatableRune] {
return trimmedTerm(runeTerm(r))
}
var (
digitTerm = runePredTerm(
stringerStr("digit"),
func(r rune) bool { return '0' <= r && r <= '9' },
)
positiveNumberTerm = runesToStringTerm(oneOrMore(digitTerm))
negativeNumberTerm = seq(
stringerStr("negative-number"),
runeTerm('-'),
positiveNumberTerm,
func(neg locatableRune, posNum locatableString) locatableString {
return locatableString{neg.locate(), string(neg.r) + posNum.str}
},
)
numberTerm = mapTerm(
stringerStr("number"),
firstOf(negativeNumberTerm, positiveNumberTerm),
func(str locatableString) Value {
i, err := strconv.ParseInt(str.str, 10, 64)
if err != nil {
panic(fmt.Errorf("parsing %q as int: %w", str, err))
}
return Value{Number: &i, Location: str.locate()}
},
)
)
var (
letterTerm = runePredTerm(
stringerStr("letter"),
func(r rune) bool {
return unicode.In(r, unicode.Letter, unicode.Mark)
},
)
letterTailTerm = zeroOrMore(firstOf(letterTerm, digitTerm))
nameTerm = seq(
stringerStr("name"),
letterTerm,
letterTailTerm,
func(head locatableRune, tail []locatableRune) Value {
name := string(head.r) + locatableRunesToString(tail)
return Value{Name: &name, Location: head.locate()}
},
)
)
func openEdgeIntoValue(val Value, oe *OpenEdge) *OpenEdge {
switch {
case oe == nil:
return graph.ValueOut(None, val)
case !oe.EdgeValue().Valid:
return oe.WithEdgeValue(Some(val))
default:
return graph.TupleOut(Some(val), oe)
}
}
var graphTerm, valueTerm = func() (*term[Value], *term[Value]) {
type tupleState struct {
ins []*OpenEdge
oe *OpenEdge
}
type graphState struct {
g *Graph
oe *OpenEdge
}
var (
rightParenthesis = trimmedRuneTerm(')')
tupleEndTerm = mapTerm(
rightParenthesis,
rightParenthesis,
func(lr locatableRune) tupleState {
// if ')', then map that to an empty state. This acts as a
// sentinel value to indicate "end of tuple".
return tupleState{}
},
)
rightCurlyBrace = trimmedRuneTerm('}')
graphEndTerm = mapTerm(
rightCurlyBrace,
rightCurlyBrace,
func(lr locatableRune) graphState {
// if '}', then map that to an empty state. This acts as a
// sentinel value to indicate "end of graph".
return graphState{}
},
)
)
var (
// pre-define these, and then fill in the pointers after, in order to
// deal with recursive dependencies between them.
valueTerm = new(term[Value])
tupleTerm = new(term[*OpenEdge])
tupleTailTerm = new(term[tupleState])
tupleOpenEdgeTerm = new(term[tupleState])
tupleOpenEdgeTailTerm = new(term[tupleState])
tupleOpenEdgeValueTailTerm = new(term[tupleState])
graphTerm = new(term[Value])
graphTailTerm = new(term[graphState])
graphOpenEdgeTerm = new(term[graphState])
graphOpenEdgeTailTerm = new(term[graphState])
graphOpenEdgeValueTailTerm = new(term[graphState])
)
*tupleTerm = *seq(
stringerStr("tuple"),
trimmedRuneTerm('('),
tupleTailTerm,
func(lr locatableRune, ts tupleState) *OpenEdge {
slices.Reverse(ts.ins)
return graph.TupleOut(None, ts.ins...)
},
)
*tupleTailTerm = *firstOf(
tupleEndTerm,
mapTerm(
tupleOpenEdgeTerm,
tupleOpenEdgeTerm,
func(ts tupleState) tupleState {
ts.ins = append(ts.ins, ts.oe)
ts.oe = nil
return ts
},
),
)
*tupleOpenEdgeTerm = *firstOf(
seq(
valueTerm,
valueTerm,
tupleOpenEdgeValueTailTerm,
func(val Value, ts tupleState) tupleState {
ts.oe = openEdgeIntoValue(val, ts.oe)
return ts
},
),
seq(
tupleTerm,
tupleTerm,
tupleOpenEdgeTailTerm,
func(oe *OpenEdge, ts tupleState) tupleState {
ts.oe = oe
return ts
},
),
)
*tupleOpenEdgeTailTerm = *firstOf(
tupleEndTerm,
prefixed(trimmedRuneTerm(','), tupleTailTerm),
)
*tupleOpenEdgeValueTailTerm = *firstOf(
tupleOpenEdgeTailTerm,
prefixed(trimmedRuneTerm('<'), tupleOpenEdgeTerm),
)
*graphTerm = *seq(
stringerStr("graph"),
trimmedRuneTerm('{'),
graphTailTerm,
func(lr locatableRune, gs graphState) Value {
if gs.g == nil {
gs.g = new(Graph)
}
return Value{Graph: gs.g, Location: lr.locate()}
},
)
*graphTailTerm = *firstOf(
graphEndTerm,
seq(
nameTerm,
nameTerm,
prefixed(trimmedRuneTerm('='), graphOpenEdgeTerm),
func(name Value, gs graphState) graphState {
if gs.g == nil {
gs.g = new(Graph)
}
gs.g = gs.g.AddValueIn(name, gs.oe)
gs.oe = nil
return gs
},
),
)
*graphOpenEdgeTerm = *firstOf(
seq(
valueTerm,
valueTerm,
graphOpenEdgeValueTailTerm,
func(val Value, gs graphState) graphState {
gs.oe = openEdgeIntoValue(val, gs.oe)
return gs
},
),
seq(
tupleTerm,
tupleTerm,
graphOpenEdgeTailTerm,
func(oe *OpenEdge, gs graphState) graphState {
gs.oe = oe
return gs
},
),
)
*graphOpenEdgeTailTerm = *firstOf(
graphEndTerm,
prefixed(trimmedRuneTerm(';'), graphTailTerm),
)
*graphOpenEdgeValueTailTerm = *firstOf(
graphOpenEdgeTailTerm,
prefixed(trimmedRuneTerm('<'), graphOpenEdgeTerm),
)
*valueTerm = *firstOf(nameTerm, numberTerm, graphTerm)
return graphTerm, valueTerm
}()
var topLevelTerm = trimmedTerm(valueTerm)

387
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package gg
import (
"bytes"
"io"
"strconv"
"testing"
"github.com/mediocregopher/ginger/graph"
"github.com/stretchr/testify/assert"
)
func decoderLeftover(d *Decoder) string {
unread := make([]rune, len(d.unread))
for i := range unread {
unread[i] = d.unread[i].r
}
rest, err := io.ReadAll(d.br)
if err != nil {
panic(err)
}
return string(unread) + string(rest)
}
func TestTermDecoding(t *testing.T) {
type test struct {
in string
exp Value
expErr string
leftover string
}
runTests := func(
t *testing.T, name string, term *term[Value], tests []test,
) {
t.Run(name, func(t *testing.T) {
for i, test := range tests {
t.Run(strconv.Itoa(i), func(t *testing.T) {
dec := NewDecoder(bytes.NewBufferString(test.in))
got, err := term.decodeFn(dec)
if test.expErr != "" {
assert.Error(t, err)
assert.Equal(t, test.expErr, err.Error())
} else if assert.NoError(t, err) {
assert.True(t,
test.exp.Equal(got),
"\nexp:%v\ngot:%v", test.exp, got,
)
assert.Equal(t, test.leftover, decoderLeftover(dec))
}
})
}
})
}
expNum := func(row, col int, n int64) Value {
return Value{Number: &n, Location: Location{row, col}}
}
runTests(t, "number", numberTerm, []test{
{in: `0`, exp: expNum(1, 1, 0)},
{in: `100`, exp: expNum(1, 1, 100)},
{in: `-100`, exp: expNum(1, 1, -100)},
{in: `0foo`, exp: expNum(1, 1, 0), leftover: "foo"},
{in: `100foo`, exp: expNum(1, 1, 100), leftover: "foo"},
})
expName := func(row, col int, name string) Value {
return Value{Name: &name, Location: Location{row, col}}
}
expGraph := func(row, col int, g *Graph) Value {
return Value{Graph: g, Location: Location{row, col}}
}
runTests(t, "name", nameTerm, []test{
{in: `a`, exp: expName(1, 1, "a")},
{in: `ab`, exp: expName(1, 1, "ab")},
{in: `ab2c`, exp: expName(1, 1, "ab2c")},
{in: `ab2c,`, exp: expName(1, 1, "ab2c"), leftover: ","},
})
runTests(t, "graph", graphTerm, []test{
{in: `{}`, exp: expGraph(1, 1, new(Graph))},
{in: `{`, expErr: `1:2: expected '}' or name`},
{in: `{a}`, expErr: `1:3: expected '='`},
{in: `{a=}`, expErr: `1:4: expected name or number or graph or tuple`},
{
in: `{foo=a}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(None, expName(6, 1, "a")),
),
),
},
{
in: `{ foo = a }`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(None, expName(6, 1, "a")),
),
),
},
{in: `{1=a}`, expErr: `1:2: expected '}' or name`},
{in: `{foo=a ,}`, expErr: `1:8: expected '}' or ';' or '<'`},
{in: `{foo=a`, expErr: `1:7: expected '}' or ';' or '<'`},
{
in: `{foo=a<b}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expName(8, 1, "b"),
),
),
),
},
{
in: `{foo=a< b <c}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.ValueOut(
Some(expName(8, 1, "b")),
expName(10, 1, "c"),
),
),
),
),
},
{
in: `{foo =a<b<c<1 }`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.TupleOut(
Some(expName(8, 1, "b")),
graph.ValueOut(
Some(expName(10, 1, "c")),
expNum(12, 1, 1),
),
),
),
),
),
},
{
in: `{foo=a<b ; }`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expName(8, 1, "b"),
),
),
),
},
{
in: `{foo=a<b;bar=c}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expName(8, 1, "b"),
),
).
AddValueIn(
expName(10, 1, "bar"),
graph.ValueOut(None, expName(15, 1, "c")),
),
),
},
{
in: `{foo= a<{ baz=1 } ; bar=c}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expGraph(8, 1, new(Graph).AddValueIn(
expName(9, 1, "baz"),
graph.ValueOut(None, expNum(13, 1, 1)),
)),
),
).
AddValueIn(
expName(16, 1, "bar"),
graph.ValueOut(None, expName(20, 1, "c")),
),
),
},
{
in: `{foo= {baz=1} <a; bar=c}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expGraph(8, 1, new(Graph).AddValueIn(
expName(9, 1, "baz"),
graph.ValueOut(None, expNum(13, 1, 1)),
))),
expName(6, 1, "a"),
),
).
AddValueIn(
expName(16, 1, "bar"),
graph.ValueOut(None, expName(20, 1, "c")),
),
),
},
})
runTests(t, "tuple", graphTerm, []test{
{
in: `{foo=(a)}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(None, expName(6, 1, "a")),
),
),
},
{
in: `{foo=(a<b)}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expName(8, 1, "b"),
),
),
),
},
{
in: `{foo=a<(b)}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(
Some(expName(6, 1, "a")),
expName(8, 1, "b"),
),
),
),
},
{
in: `{foo=a<(b,c)}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.ValueOut(None, expName(8, 1, "b")),
graph.ValueOut(None, expName(10, 1, "c")),
),
),
),
},
{
in: `{foo=a<(b<c)}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.TupleOut(
Some(expName(6, 1, "b")),
graph.ValueOut(None, expName(8, 1, "c")),
),
),
),
),
},
{
in: `{foo=a<(b<(c))}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.TupleOut(
Some(expName(6, 1, "b")),
graph.ValueOut(None, expName(8, 1, "c")),
),
),
),
),
},
{
in: `{foo=a<(b<(c,d<1))}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.TupleOut(
Some(expName(6, 1, "b")),
graph.ValueOut(None, expName(8, 1, "c")),
graph.ValueOut(
Some(expName(12, 1, "d")),
expNum(10, 1, 1),
),
),
),
),
),
},
{
in: `{foo=a<(b<( ( (c) ) ))}`,
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.TupleOut(
Some(expName(6, 1, "a")),
graph.TupleOut(
Some(expName(6, 1, "b")),
graph.ValueOut(None, expName(8, 1, "c")),
),
),
),
),
},
})
runTests(t, "comment", graphTerm, []test{
{
in: "*\n{}",
exp: expGraph(1, 1, new(Graph)),
},
{
in: "* ignore me!\n{}",
exp: expGraph(1, 1, new(Graph)),
},
{
in: "{* ignore me!\n}",
exp: expGraph(1, 1, new(Graph)),
},
{
in: "{foo* ignore me!\n = a}",
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(None, expName(6, 1, "a")),
),
),
},
{
in: "{foo = a* ignore me!\n}",
exp: expGraph(
1, 1, new(Graph).
AddValueIn(
expName(2, 1, "foo"),
graph.ValueOut(None, expName(6, 1, "a")),
),
),
},
})
}

23
gg/util_test.go
View File

@ -1,23 +0,0 @@
package gg
import "io"
type mockReader struct {
body []byte
err error
}
func (r *mockReader) Read(b []byte) (int, error) {
n := copy(b, r.body)
r.body = r.body[n:]
if len(r.body) == 0 {
if r.err == nil {
return n, io.EOF
}
return n, r.err
}
return n, nil
}

1
go.mod
View File

@ -7,5 +7,6 @@ require github.com/stretchr/testify v1.7.0
require ( require (
github.com/davecgh/go-spew v1.1.0 // indirect github.com/davecgh/go-spew v1.1.0 // indirect
github.com/pmezard/go-difflib v1.0.0 // indirect github.com/pmezard/go-difflib v1.0.0 // indirect
golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
) )

2
go.sum
View File

@ -5,6 +5,8 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY= github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM= gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo= gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=

3
graph/graph.go
View File

@ -126,7 +126,7 @@ func TupleOut[E, V Value](edgeVal E, ins ...*OpenEdge[E, V]) *OpenEdge[E, V] {
if len(ins) == 1 { if len(ins) == 1 {
var ( var (
zero V zero E
in = ins[0] in = ins[0]
) )
@ -353,7 +353,6 @@ type reducedEdge[Ea, Va Value, Vb any] struct {
// If a value or edge is connected to multiple times within the root OpenEdge it // If a value or edge is connected to multiple times within the root OpenEdge it
// will only be mapped/reduced a single time, and the result of that single // will only be mapped/reduced a single time, and the result of that single
// map/reduction will be passed to each dependant operation. // map/reduction will be passed to each dependant operation.
//
func MapReduce[Ea, Va Value, Vb any]( func MapReduce[Ea, Va Value, Vb any](
root *OpenEdge[Ea, Va], root *OpenEdge[Ea, Va],
mapVal func(Va) (Vb, error), mapVal func(Va) (Vb, error),

233
vm/function.go Normal file
View File

@ -0,0 +1,233 @@
package vm
import (
"fmt"
"github.com/mediocregopher/ginger/gg"
"github.com/mediocregopher/ginger/graph"
)
// Function is an entity which accepts an argument Value and performs some
// internal processing on that argument to return a resultant Value.
type Function interface {
Perform(Value) Value
}
// FunctionFunc is a function which implements the Function interface.
type FunctionFunc func(Value) Value
// Perform calls the underlying FunctionFunc directly.
func (f FunctionFunc) Perform(arg Value) Value {
return f(arg)
}
// Identity returns an Function which always returns the given Value,
// regardless of the input argument.
//
// TODO this might not be the right name
func Identity(val Value) Function {
return FunctionFunc(func(Value) Value {
return val
})
}
var (
valNameIn = Value{Value: gg.Name("in")}
valNameOut = Value{Value: gg.Name("out")}
valNameIf = Value{Value: gg.Name("if")}
valNameRecur = Value{Value: gg.Name("recur")}
valNumberZero = Value{Value: gg.Number(0)}
)
// FunctionFromGraph wraps the given Graph such that it can be used as an
// Function. The given Scope determines what values outside of the Graph are
// available for use within the Function.
func FunctionFromGraph(g *gg.Graph, scope Scope) (Function, error) {
// edgeFn is distinct from a generic Function in that the Value passed into
// Perform will _always_ be the value of "in" for the overall Function.
//
// edgeFns will wrap each other, passing "in" downwards to the leaf edgeFns.
type edgeFn Function
var compileEdge func(*gg.OpenEdge) (edgeFn, error)
// TODO memoize?
valToEdgeFn := func(val Value) (edgeFn, error) {
if val.Name == nil {
return edgeFn(Identity(val)), nil
}
name := *val.Name
if val.Equal(valNameIn) {
return edgeFn(FunctionFunc(func(inArg Value) Value {
return inArg
})), nil
}
// TODO intercept if and recur?
edgesIn := g.ValueIns(val.Value)
if l := len(edgesIn); l == 0 {
val, err := scope.Resolve(name)
if err != nil {
return nil, fmt.Errorf("resolving name %q from the outer scope: %w", name, err)
}
return edgeFn(Identity(val)), nil
} else if l != 1 {
return nil, fmt.Errorf("resolved name %q to %d input edges, rather than one", name, l)
}
edge := edgesIn[0]
return compileEdge(edge)
}
// "out" resolves to more than a static value, treat the graph as a full
// operation.
// thisFn is used to support recur. It will get filled in with the Function
// which is returned by this function, once that Function is created.
thisFn := new(Function)
compileEdge = func(edge *gg.OpenEdge) (edgeFn, error) {
return graph.MapReduce[gg.OptionalValue, gg.Value, edgeFn](
edge,
func(ggVal gg.Value) (edgeFn, error) {
return valToEdgeFn(Value{Value: ggVal})
},
func(ggEdgeVal gg.OptionalValue, inEdgeFns []edgeFn) (edgeFn, error) {
if ggEdgeVal.Equal(valNameIf.Value) {
if len(inEdgeFns) != 3 {
return nil, fmt.Errorf("'if' requires a 3-tuple argument")
}
return edgeFn(FunctionFunc(func(inArg Value) Value {
if pred := inEdgeFns[0].Perform(inArg); pred.Equal(valNumberZero) {
return inEdgeFns[2].Perform(inArg)
}
return inEdgeFns[1].Perform(inArg)
})), nil
}
// "if" statements (above) are the only case where we want the
// input edges to remain separated, otherwise they should always
// be combined into a single edge whose value is a tuple. Do
// that here.
inEdgeFn := inEdgeFns[0]
if len(inEdgeFns) > 1 {
inEdgeFn = edgeFn(FunctionFunc(func(inArg Value) Value {
tupVals := make([]Value, len(inEdgeFns))
for i := range inEdgeFns {
tupVals[i] = inEdgeFns[i].Perform(inArg)
}
return Tuple(tupVals...)
}))
}
var edgeVal Value
if ggEdgeVal.Valid {
edgeVal.Value = ggEdgeVal.Value
}
if edgeVal.IsZero() {
return inEdgeFn, nil
}
if edgeVal.Equal(valNameRecur) {
return edgeFn(FunctionFunc(func(inArg Value) Value {
return (*thisFn).Perform(inEdgeFn.Perform(inArg))
})), nil
}
if edgeVal.Graph != nil {
opFromGraph, err := FunctionFromGraph(
edgeVal.Graph,
scope.NewScope(),
)
if err != nil {
return nil, fmt.Errorf("compiling graph to operation: %w", err)
}
edgeVal = Value{Function: opFromGraph}
}
// The Function is known at compile-time, so we can wrap it
// directly into an edgeVal using the existing inEdgeFn as the
// input.
if edgeVal.Function != nil {
return edgeFn(FunctionFunc(func(inArg Value) Value {
return edgeVal.Function.Perform(inEdgeFn.Perform(inArg))
})), nil
}
// the edgeVal is not an Function at compile time, and so
// it must become one at runtime. We must resolve edgeVal to an
// edgeFn as well (edgeEdgeFn), and then at runtime that is
// given the inArg and (hopefully) the resultant Function is
// called.
edgeEdgeFn, err := valToEdgeFn(edgeVal)
if err != nil {
return nil, err
}
return edgeFn(FunctionFunc(func(inArg Value) Value {
runtimeEdgeVal := edgeEdgeFn.Perform(inArg)
if runtimeEdgeVal.Graph != nil {
runtimeFn, err := FunctionFromGraph(
runtimeEdgeVal.Graph,
scope.NewScope(),
)
if err != nil {
panic(fmt.Sprintf("compiling graph to operation: %v", err))
}
runtimeEdgeVal = Value{Function: runtimeFn}
}
if runtimeEdgeVal.Function == nil {
panic("edge value must be an operation")
}
return runtimeEdgeVal.Function.Perform(inEdgeFn.Perform(inArg))
})), nil
},
)
}
graphFn, err := valToEdgeFn(valNameOut)
if err != nil {
return nil, err
}
*thisFn = Function(graphFn)
return Function(graphFn), nil
}

235
vm/op.go
View File

@ -1,235 +0,0 @@
package vm
import (
"fmt"
"github.com/mediocregopher/ginger/gg"
"github.com/mediocregopher/ginger/graph"
)
// Operation is an entity which accepts an argument Value and performs some
// internal processing on that argument to return a resultant Value.
type Operation interface {
Perform(Value) Value
}
// OperationFunc is a function which implements the Operation interface.
type OperationFunc func(Value) Value
// Perform calls the underlying OperationFunc directly.
func (f OperationFunc) Perform(arg Value) Value {
return f(arg)
}
// Identity returns an Operation which always returns the given Value,
// regardless of the input argument.
//
// TODO this might not be the right name
func Identity(val Value) Operation {
return OperationFunc(func(Value) Value {
return val
})
}
type graphOp struct {
*gg.Graph
scope Scope
}
var (
valNameIn = Value{Value: gg.Name("in")}
valNameOut = Value{Value: gg.Name("out")}
valNameIf = Value{Value: gg.Name("if")}
valNameRecur = Value{Value: gg.Name("recur")}
valNumberZero = Value{Value: gg.Number(0)}
)
// OperationFromGraph wraps the given Graph such that it can be used as an
// Operation. The given Scope determines what values outside of the Graph are
// available for use within the Operation.
func OperationFromGraph(g *gg.Graph, scope Scope) (Operation, error) {
// edgeOp is distinct from a generic Operation in that the Value passed into
// Perform will _always_ be the value of "in" for the overall Operation.
//
// edgeOps will wrap each other, passing "in" downwards to the leaf edgeOps.
type edgeOp Operation
var compileEdge func(*gg.OpenEdge) (edgeOp, error)
// TODO memoize?
valToEdgeOp := func(val Value) (edgeOp, error) {
if val.Name == nil {
return edgeOp(Identity(val)), nil
}
name := *val.Name
if val.Equal(valNameIn) {
return edgeOp(OperationFunc(func(inArg Value) Value {
return inArg
})), nil
}
// TODO intercept if and recur?
edgesIn := g.ValueIns(val.Value)
if l := len(edgesIn); l == 0 {
val, err := scope.Resolve(name)
if err != nil {
return nil, fmt.Errorf("resolving name %q from the outer scope: %w", name, err)
}
return edgeOp(Identity(val)), nil
} else if l != 1 {
return nil, fmt.Errorf("resolved name %q to %d input edges, rather than one", name, l)
}
edge := edgesIn[0]
return compileEdge(edge)
}
// "out" resolves to more than a static value, treat the graph as a full
// operation.
// thisOp is used to support recur. It will get filled in with the Operation
// which is returned by this function, once that Operation is created.
thisOp := new(Operation)
compileEdge = func(edge *gg.OpenEdge) (edgeOp, error) {
return graph.MapReduce[gg.Value, gg.Value, edgeOp](
edge,
func(ggVal gg.Value) (edgeOp, error) {
return valToEdgeOp(Value{Value: ggVal})
},
func(ggEdgeVal gg.Value, inEdgeOps []edgeOp) (edgeOp, error) {
if ggEdgeVal.Equal(valNameIf.Value) {
if len(inEdgeOps) != 3 {
return nil, fmt.Errorf("'if' requires a 3-tuple argument")
}
return edgeOp(OperationFunc(func(inArg Value) Value {
if pred := inEdgeOps[0].Perform(inArg); pred.Equal(valNumberZero) {
return inEdgeOps[2].Perform(inArg)
}
return inEdgeOps[1].Perform(inArg)
})), nil
}
// "if" statements (above) are the only case where we want the
// input edges to remain separated, otherwise they should always
// be combined into a single edge whose value is a tuple. Do
// that here.
inEdgeOp := inEdgeOps[0]
if len(inEdgeOps) > 1 {
inEdgeOp = edgeOp(OperationFunc(func(inArg Value) Value {
tupVals := make([]Value, len(inEdgeOps))
for i := range inEdgeOps {
tupVals[i] = inEdgeOps[i].Perform(inArg)
}
return Tuple(tupVals...)
}))
}
edgeVal := Value{Value: ggEdgeVal}
if edgeVal.IsZero() {
return inEdgeOp, nil
}
if edgeVal.Equal(valNameRecur) {
return edgeOp(OperationFunc(func(inArg Value) Value {
return (*thisOp).Perform(inEdgeOp.Perform(inArg))
})), nil
}
if edgeVal.Graph != nil {
opFromGraph, err := OperationFromGraph(
edgeVal.Graph,
scope.NewScope(),
)
if err != nil {
return nil, fmt.Errorf("compiling graph to operation: %w", err)
}
edgeVal = Value{Operation: opFromGraph}
}
// The Operation is known at compile-time, so we can wrap it
// directly into an edgeVal using the existing inEdgeOp as the
// input.
if edgeVal.Operation != nil {
return edgeOp(OperationFunc(func(inArg Value) Value {
return edgeVal.Operation.Perform(inEdgeOp.Perform(inArg))
})), nil
}
// the edgeVal is not an Operation at compile time, and so
// it must become one at runtime. We must resolve edgeVal to an
// edgeOp as well (edgeEdgeOp), and then at runtime that is
// given the inArg and (hopefully) the resultant Operation is
// called.
edgeEdgeOp, err := valToEdgeOp(edgeVal)
if err != nil {
return nil, err
}
return edgeOp(OperationFunc(func(inArg Value) Value {
runtimeEdgeVal := edgeEdgeOp.Perform(inArg)
if runtimeEdgeVal.Graph != nil {
runtimeOp, err := OperationFromGraph(
runtimeEdgeVal.Graph,
scope.NewScope(),
)
if err != nil {
panic(fmt.Sprintf("compiling graph to operation: %v", err))
}
runtimeEdgeVal = Value{Operation: runtimeOp}
}
if runtimeEdgeVal.Operation == nil {
panic("edge value must be an operation")
}
return runtimeEdgeVal.Operation.Perform(inEdgeOp.Perform(inArg))
})), nil
},
)
}
graphOp, err := valToEdgeOp(valNameOut)
if err != nil {
return nil, err
}
*thisOp = Operation(graphOp)
return Operation(graphOp), nil
}

65
vm/scope.go
View File

@ -2,8 +2,6 @@ package vm
import ( import (
"fmt" "fmt"
"github.com/mediocregopher/ginger/gg"
) )
// Scope encapsulates a set of name->Value mappings. // Scope encapsulates a set of name->Value mappings.
@ -62,66 +60,3 @@ func (s *scopeWith) Resolve(name string) (Value, error) {
} }
return s.Scope.Resolve(name) return s.Scope.Resolve(name)
} }
type graphScope struct {
*gg.Graph
parent Scope
}
/*
TODO I don't think this is actually necessary
// ScopeFromGraph returns a Scope which will use the given Graph for name
// resolution.
//
// When a name is resolved, that name will be looked up in the Graph. The name's
// vertex must have only a single OpenEdge leading to it. That edge will be
// compiled into an Operation and returned.
//
// If a name does not appear in the Graph, then the given parent Scope will be
// used to resolve that name. If the parent Scope is nil then an error is
// returned.
//
// NewScope will return the parent scope, if one is given, or an empty ScopeMap
// if not.
func ScopeFromGraph(g *gg.Graph, parent Scope) Scope {
return &graphScope{
Graph: g,
parent: parent,
}
}
func (g *graphScope) Resolve(name string) (Value, error) {
var ggNameVal gg.Value
ggNameVal.Name = &name
log.Printf("resolving %q", name)
edgesIn := g.ValueIns(ggNameVal)
if l := len(edgesIn); l == 0 && g.parent != nil {
return g.parent.Resolve(name)
} else if l != 1 {
return nil, fmt.Errorf(
"%q must have exactly one input edge, found %d input edges",
name, l,
)
}
return CompileEdge(edgesIn[0], g)
}
func (g *graphScope) NewScope() Scope {
if g.parent == nil {
return ScopeMap{}
}
return g.parent
}
*/

10
vm/scope_global.go
View File

@ -6,9 +6,9 @@ import (
"github.com/mediocregopher/ginger/gg" "github.com/mediocregopher/ginger/gg"
) )
func globalOp(fn func(Value) (Value, error)) Value { func globalFn(fn func(Value) (Value, error)) Value {
return Value{ return Value{
Operation: OperationFunc(func(in Value) Value { Function: FunctionFunc(func(in Value) Value {
res, err := fn(in) res, err := fn(in)
if err != nil { if err != nil {
panic(err) panic(err)
@ -22,7 +22,7 @@ func globalOp(fn func(Value) (Value, error)) Value {
// any operation in a ginger program. // any operation in a ginger program.
var GlobalScope = ScopeMap{ var GlobalScope = ScopeMap{
"add": globalOp(func(val Value) (Value, error) { "add": globalFn(func(val Value) (Value, error) {
var sum int64 var sum int64
@ -39,7 +39,7 @@ var GlobalScope = ScopeMap{
}), }),
"tupEl": globalOp(func(val Value) (Value, error) { "tupEl": globalFn(func(val Value) (Value, error) {
tup, i := val.Tuple[0], val.Tuple[1] tup, i := val.Tuple[0], val.Tuple[1]
@ -47,7 +47,7 @@ var GlobalScope = ScopeMap{
}), }),
"isZero": globalOp(func(val Value) (Value, error) { "isZero": globalFn(func(val Value) (Value, error) {
if *val.Number == 0 { if *val.Number == 0 {
one := int64(1) one := int64(1)

40
vm/vm.go
View File

@ -2,6 +2,7 @@
package vm package vm
import ( import (
"errors"
"fmt" "fmt"
"io" "io"
"strings" "strings"
@ -13,12 +14,12 @@ import (
// ZeroValue is a Value with no fields set. It is equivalent to the 0-tuple. // ZeroValue is a Value with no fields set. It is equivalent to the 0-tuple.
var ZeroValue Value var ZeroValue Value
// Value extends a gg.Value to include Operations and Tuples as a possible // Value extends a gg.Value to include Functions and Tuples as a possible
// types. // types.
type Value struct { type Value struct {
gg.Value gg.Value
Operation Function
Tuple []Value Tuple []Value
} }
@ -44,11 +45,11 @@ func (v Value) Equal(v2g graph.Value) bool {
switch { switch {
case !v.Value.IsZero() || !v2.Value.IsZero(): case (v.Value != (gg.Value{}) || v2.Value != (gg.Value{})):
return v.Value.Equal(v2.Value) return v.Value.Equal(v2.Value)
case v.Operation != nil || v2.Operation != nil: case v.Function != nil || v2.Function != nil:
// for now we say that Operations can't be compared. This will probably // for now we say that Functions can't be compared. This will probably
// get revisted later. // get revisted later.
return false return false
@ -76,12 +77,12 @@ func (v Value) String() string {
switch { switch {
case v.Operation != nil: case v.Function != nil:
// We can try to get better strings for ops later // We can try to get better strings for ops later
return "<op>" return "<fn>"
case !v.Value.IsZero(): case v.Value != (gg.Value{}):
return v.Value.String() return v.Value.String()
default: default:
@ -100,30 +101,23 @@ func (v Value) String() string {
} }
func nameVal(n string) Value {
var val Value
val.Name = &n
return val
}
// EvaluateSource reads and parses the io.Reader as an operation, input is used // EvaluateSource reads and parses the io.Reader as an operation, input is used
// as the argument to the operation, and the resultant value is returned. // as the argument to the operation, and the resultant value is returned.
// //
// scope contains pre-defined operations and values which are available during // scope contains pre-defined operations and values which are available during
// the evaluation. // the evaluation.
func EvaluateSource(opSrc io.Reader, input Value, scope Scope) (Value, error) { func EvaluateSource(opSrc io.Reader, input Value, scope Scope) (Value, error) {
lexer := gg.NewLexer(opSrc) v, err := gg.NewDecoder(opSrc).Next()
if err != nil {
return Value{}, err
} else if v.Graph == nil {
return Value{}, errors.New("value must be a graph")
}
g, err := gg.DecodeLexer(lexer) fn, err := FunctionFromGraph(v.Graph, scope.NewScope())
if err != nil { if err != nil {
return Value{}, err return Value{}, err
} }
op, err := OperationFromGraph(g, scope.NewScope()) return fn.Perform(input), nil
if err != nil {
return Value{}, err
}
return op.Perform(input), nil
} }

6
vm/vm_test.go
View File

@ -10,11 +10,11 @@ import (
func TestVM(t *testing.T) { func TestVM(t *testing.T) {
src := ` src := `{
incr = { out = add < (1; in;); }; incr = { out = add < (1, in); };
out = incr < incr < in; out = incr < incr < in;
` }`
var in int64 = 5 var in int64 = 5