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move parsing stuff in expr into its own set of files

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This commit is contained in:
Brian Picciano 2016-07-28 17:10:47 -06:00
parent d48bcf34b8
commit f5facb6506
3 changed files with 304 additions and 299 deletions
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299
expr/expr.go
View File

@ -2,8 +2,6 @@ package expr
import ( import (
"fmt" "fmt"
"io"
"strconv"
"strings" "strings"
"llvm.org/llvm/bindings/go/llvm" "llvm.org/llvm/bindings/go/llvm"
@ -266,300 +264,3 @@ func (b Block) equal(e equaler) bool {
} }
return true return true
} }
////////////////////////////////////////////////////////////////////////////////
type exprErr struct {
reason string
err error
tok lexer.Token
tokCtx string // e.g. "block starting at" or "open paren at"
}
func (e exprErr) Error() string {
var msg string
if e.err != nil {
msg = e.err.Error()
} else {
msg = e.reason
}
if err := e.tok.Err(); err != nil {
msg += " - token error: " + err.Error()
} else if (e.tok != lexer.Token{}) {
msg += " - "
if e.tokCtx != "" {
msg += e.tokCtx + ": "
}
msg = fmt.Sprintf("%s [line:%d col:%d]", msg, e.tok.Row, e.tok.Col)
}
return msg
}
////////////////////////////////////////////////////////////////////////////////
// toks[0] must be start
func sliceEnclosedToks(toks []lexer.Token, start, end lexer.Token) ([]lexer.Token, []lexer.Token, error) {
c := 1
ret := []lexer.Token{}
first := toks[0]
for i, tok := range toks[1:] {
if tok.Err() != nil {
return nil, nil, exprErr{
reason: fmt.Sprintf("missing closing %v", end),
tok: tok,
}
}
if tok.Equal(start) {
c++
} else if tok.Equal(end) {
c--
}
if c == 0 {
return ret, toks[2+i:], nil
}
ret = append(ret, tok)
}
return nil, nil, exprErr{
reason: fmt.Sprintf("missing closing %v", end),
tok: first,
tokCtx: "starting at",
}
}
// Parse reads in all expressions it can from the given io.Reader and returns
// them
func Parse(r io.Reader) ([]Expr, error) {
toks := readAllToks(r)
var ret []Expr
var expr Expr
var err error
for len(toks) > 0 {
if toks[0].TokenType == lexer.EOF {
return ret, nil
}
expr, toks, err = parse(toks)
if err != nil {
return nil, err
}
ret = append(ret, expr)
}
return ret, nil
}
// ParseAsBlock reads the given io.Reader as if it was implicitly surrounded by
// curly braces, making it into a Block. This means all expressions from the
// io.Reader *must* be statements. The returned Expr's Actual will always be a
// Block.
func ParseAsBlock(r io.Reader) (Expr, error) {
return parseBlock(readAllToks(r))
}
func readAllToks(r io.Reader) []lexer.Token {
l := lexer.New(r)
var toks []lexer.Token
for l.HasNext() {
toks = append(toks, l.Next())
}
return toks
}
// For all parse methods it is assumed that toks is not empty
var (
openParen = lexer.Token{TokenType: lexer.Wrapper, Val: "("}
closeParen = lexer.Token{TokenType: lexer.Wrapper, Val: ")"}
openCurly = lexer.Token{TokenType: lexer.Wrapper, Val: "{"}
closeCurly = lexer.Token{TokenType: lexer.Wrapper, Val: "}"}
comma = lexer.Token{TokenType: lexer.Punctuation, Val: ","}
arrow = lexer.Token{TokenType: lexer.Punctuation, Val: ">"}
)
func parse(toks []lexer.Token) (Expr, []lexer.Token, error) {
expr, toks, err := parseSingle(toks)
if err != nil {
return Expr{}, nil, err
}
if len(toks) > 0 && toks[0].TokenType == lexer.Punctuation {
return parseConnectingPunct(toks, expr)
}
return expr, toks, nil
}
func parseSingle(toks []lexer.Token) (Expr, []lexer.Token, error) {
var expr Expr
var err error
if toks[0].Err() != nil {
return Expr{}, nil, exprErr{
reason: "could not parse token",
tok: toks[0],
}
}
if toks[0].Equal(openParen) {
starter := toks[0]
var ptoks []lexer.Token
ptoks, toks, err = sliceEnclosedToks(toks, openParen, closeParen)
if err != nil {
return Expr{}, nil, err
}
if expr, ptoks, err = parse(ptoks); err != nil {
return Expr{}, nil, err
} else if len(ptoks) > 0 {
return Expr{}, nil, exprErr{
reason: "multiple expressions inside parenthesis",
tok: starter,
tokCtx: "starting at",
}
}
return expr, toks, nil
} else if toks[0].Equal(openCurly) {
var btoks []lexer.Token
btoks, toks, err = sliceEnclosedToks(toks, openCurly, closeCurly)
if err != nil {
return Expr{}, nil, err
}
if expr, err = parseBlock(btoks); err != nil {
return Expr{}, nil, err
}
return expr, toks, nil
}
if expr, err = parseNonPunct(toks[0]); err != nil {
return Expr{}, nil, err
}
return expr, toks[1:], nil
}
func parseNonPunct(tok lexer.Token) (Expr, error) {
if tok.TokenType == lexer.Identifier {
return parseIdentifier(tok)
} else if tok.TokenType == lexer.String {
return parseString(tok)
}
return Expr{}, exprErr{
reason: "unexpected non-punctuation token",
tok: tok,
}
}
func parseIdentifier(t lexer.Token) (Expr, error) {
e := Expr{Token: t}
if t.Val[0] == '-' || (t.Val[0] >= '0' && t.Val[0] <= '9') {
n, err := strconv.ParseInt(t.Val, 10, 64)
if err != nil {
return Expr{}, exprErr{
err: err,
tok: t,
}
}
e.Actual = Int(n)
} else if t.Val == "%true" {
e.Actual = Bool(true)
} else if t.Val == "%false" {
e.Actual = Bool(false)
} else if t.Val[0] == '%' {
e.Actual = Macro(t.Val[1:])
} else {
e.Actual = Identifier(t.Val)
}
return e, nil
}
func parseString(t lexer.Token) (Expr, error) {
str, err := strconv.Unquote(t.Val)
if err != nil {
return Expr{}, exprErr{
err: err,
tok: t,
}
}
return Expr{Token: t, Actual: String(str)}, nil
}
func parseConnectingPunct(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
if toks[0].Equal(comma) {
return parseTuple(toks, root)
} else if toks[0].Equal(arrow) {
expr, toks, err := parse(toks[1:])
if err != nil {
return Expr{}, nil, err
}
return Expr{Token: root.Token, Actual: Statement{In: root, To: expr}}, toks, nil
}
return root, toks, nil
}
func parseTuple(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
rootTup, ok := root.Actual.(Tuple)
if !ok {
rootTup = Tuple{root}
}
// rootTup is modified throughout, be we need to make it into an Expr for
// every return, which is annoying. so make a function to do it on the fly
mkRoot := func() Expr {
return Expr{Token: rootTup[0].Token, Actual: rootTup}
}
if len(toks) < 2 {
return mkRoot(), toks, nil
} else if !toks[0].Equal(comma) {
if toks[0].TokenType == lexer.Punctuation {
return parseConnectingPunct(toks, mkRoot())
}
return mkRoot(), toks, nil
}
var expr Expr
var err error
if expr, toks, err = parseSingle(toks[1:]); err != nil {
return Expr{}, nil, err
}
rootTup = append(rootTup, expr)
return parseTuple(toks, mkRoot())
}
// parseBlock assumes that the given token list is the entire block, already
// pulled from outer curly braces by sliceEnclosedToks, or determined to be the
// entire block in some other way.
func parseBlock(toks []lexer.Token) (Expr, error) {
b := Block{}
first := toks[0]
var expr Expr
var err error
for {
if len(toks) == 0 {
return Expr{Token: first, Actual: b}, nil
}
if expr, toks, err = parse(toks); err != nil {
return Expr{}, err
}
stmt, ok := expr.Actual.(Statement)
if !ok {
return Expr{}, exprErr{
reason: "blocks may only contain full statements",
tok: expr.Token,
tokCtx: "non-statement here",
}
}
b = append(b, stmt)
}
}

304
expr/parse.go Normal file
View File

@ -0,0 +1,304 @@
package expr
import (
"fmt"
"io"
"strconv"
"github.com/mediocregopher/ginger/lexer"
)
type exprErr struct {
reason string
err error
tok lexer.Token
tokCtx string // e.g. "block starting at" or "open paren at"
}
func (e exprErr) Error() string {
var msg string
if e.err != nil {
msg = e.err.Error()
} else {
msg = e.reason
}
if err := e.tok.Err(); err != nil {
msg += " - token error: " + err.Error()
} else if (e.tok != lexer.Token{}) {
msg += " - "
if e.tokCtx != "" {
msg += e.tokCtx + ": "
}
msg = fmt.Sprintf("%s [line:%d col:%d]", msg, e.tok.Row, e.tok.Col)
}
return msg
}
////////////////////////////////////////////////////////////////////////////////
// toks[0] must be start
func sliceEnclosedToks(toks []lexer.Token, start, end lexer.Token) ([]lexer.Token, []lexer.Token, error) {
c := 1
ret := []lexer.Token{}
first := toks[0]
for i, tok := range toks[1:] {
if tok.Err() != nil {
return nil, nil, exprErr{
reason: fmt.Sprintf("missing closing %v", end),
tok: tok,
}
}
if tok.Equal(start) {
c++
} else if tok.Equal(end) {
c--
}
if c == 0 {
return ret, toks[2+i:], nil
}
ret = append(ret, tok)
}
return nil, nil, exprErr{
reason: fmt.Sprintf("missing closing %v", end),
tok: first,
tokCtx: "starting at",
}
}
// Parse reads in all expressions it can from the given io.Reader and returns
// them
func Parse(r io.Reader) ([]Expr, error) {
toks := readAllToks(r)
var ret []Expr
var expr Expr
var err error
for len(toks) > 0 {
if toks[0].TokenType == lexer.EOF {
return ret, nil
}
expr, toks, err = parse(toks)
if err != nil {
return nil, err
}
ret = append(ret, expr)
}
return ret, nil
}
// ParseAsBlock reads the given io.Reader as if it was implicitly surrounded by
// curly braces, making it into a Block. This means all expressions from the
// io.Reader *must* be statements. The returned Expr's Actual will always be a
// Block.
func ParseAsBlock(r io.Reader) (Expr, error) {
return parseBlock(readAllToks(r))
}
func readAllToks(r io.Reader) []lexer.Token {
l := lexer.New(r)
var toks []lexer.Token
for l.HasNext() {
toks = append(toks, l.Next())
}
return toks
}
// For all parse methods it is assumed that toks is not empty
var (
openParen = lexer.Token{TokenType: lexer.Wrapper, Val: "("}
closeParen = lexer.Token{TokenType: lexer.Wrapper, Val: ")"}
openCurly = lexer.Token{TokenType: lexer.Wrapper, Val: "{"}
closeCurly = lexer.Token{TokenType: lexer.Wrapper, Val: "}"}
comma = lexer.Token{TokenType: lexer.Punctuation, Val: ","}
arrow = lexer.Token{TokenType: lexer.Punctuation, Val: ">"}
)
func parse(toks []lexer.Token) (Expr, []lexer.Token, error) {
expr, toks, err := parseSingle(toks)
if err != nil {
return Expr{}, nil, err
}
if len(toks) > 0 && toks[0].TokenType == lexer.Punctuation {
return parseConnectingPunct(toks, expr)
}
return expr, toks, nil
}
func parseSingle(toks []lexer.Token) (Expr, []lexer.Token, error) {
var expr Expr
var err error
if toks[0].Err() != nil {
return Expr{}, nil, exprErr{
reason: "could not parse token",
tok: toks[0],
}
}
if toks[0].Equal(openParen) {
starter := toks[0]
var ptoks []lexer.Token
ptoks, toks, err = sliceEnclosedToks(toks, openParen, closeParen)
if err != nil {
return Expr{}, nil, err
}
if expr, ptoks, err = parse(ptoks); err != nil {
return Expr{}, nil, err
} else if len(ptoks) > 0 {
return Expr{}, nil, exprErr{
reason: "multiple expressions inside parenthesis",
tok: starter,
tokCtx: "starting at",
}
}
return expr, toks, nil
} else if toks[0].Equal(openCurly) {
var btoks []lexer.Token
btoks, toks, err = sliceEnclosedToks(toks, openCurly, closeCurly)
if err != nil {
return Expr{}, nil, err
}
if expr, err = parseBlock(btoks); err != nil {
return Expr{}, nil, err
}
return expr, toks, nil
}
if expr, err = parseNonPunct(toks[0]); err != nil {
return Expr{}, nil, err
}
return expr, toks[1:], nil
}
func parseNonPunct(tok lexer.Token) (Expr, error) {
if tok.TokenType == lexer.Identifier {
return parseIdentifier(tok)
} else if tok.TokenType == lexer.String {
return parseString(tok)
}
return Expr{}, exprErr{
reason: "unexpected non-punctuation token",
tok: tok,
}
}
func parseIdentifier(t lexer.Token) (Expr, error) {
e := Expr{Token: t}
if t.Val[0] == '-' || (t.Val[0] >= '0' && t.Val[0] <= '9') {
n, err := strconv.ParseInt(t.Val, 10, 64)
if err != nil {
return Expr{}, exprErr{
err: err,
tok: t,
}
}
e.Actual = Int(n)
} else if t.Val == "%true" {
e.Actual = Bool(true)
} else if t.Val == "%false" {
e.Actual = Bool(false)
} else if t.Val[0] == '%' {
e.Actual = Macro(t.Val[1:])
} else {
e.Actual = Identifier(t.Val)
}
return e, nil
}
func parseString(t lexer.Token) (Expr, error) {
str, err := strconv.Unquote(t.Val)
if err != nil {
return Expr{}, exprErr{
err: err,
tok: t,
}
}
return Expr{Token: t, Actual: String(str)}, nil
}
func parseConnectingPunct(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
if toks[0].Equal(comma) {
return parseTuple(toks, root)
} else if toks[0].Equal(arrow) {
expr, toks, err := parse(toks[1:])
if err != nil {
return Expr{}, nil, err
}
return Expr{Token: root.Token, Actual: Statement{In: root, To: expr}}, toks, nil
}
return root, toks, nil
}
func parseTuple(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
rootTup, ok := root.Actual.(Tuple)
if !ok {
rootTup = Tuple{root}
}
// rootTup is modified throughout, be we need to make it into an Expr for
// every return, which is annoying. so make a function to do it on the fly
mkRoot := func() Expr {
return Expr{Token: rootTup[0].Token, Actual: rootTup}
}
if len(toks) < 2 {
return mkRoot(), toks, nil
} else if !toks[0].Equal(comma) {
if toks[0].TokenType == lexer.Punctuation {
return parseConnectingPunct(toks, mkRoot())
}
return mkRoot(), toks, nil
}
var expr Expr
var err error
if expr, toks, err = parseSingle(toks[1:]); err != nil {
return Expr{}, nil, err
}
rootTup = append(rootTup, expr)
return parseTuple(toks, mkRoot())
}
// parseBlock assumes that the given token list is the entire block, already
// pulled from outer curly braces by sliceEnclosedToks, or determined to be the
// entire block in some other way.
func parseBlock(toks []lexer.Token) (Expr, error) {
b := Block{}
first := toks[0]
var expr Expr
var err error
for {
if len(toks) == 0 {
return Expr{Token: first, Actual: b}, nil
}
if expr, toks, err = parse(toks); err != nil {
return Expr{}, err
}
stmt, ok := expr.Actual.(Statement)
if !ok {
return Expr{}, exprErr{
reason: "blocks may only contain full statements",
tok: expr.Token,
tokCtx: "non-statement here",
}
}
b = append(b, stmt)
}
}

0
expr/expr_test.go → expr/parse_test.go
View File