fix problem with arrow not connecting if the left side was a tuple

expr/expr.go

@@ -310,10 +310,10 @@ func readAllToks(r io.Reader) []lexer.Token {
 // For all parse methods it is assumed that toks is not empty
 
 var (
-	openParen  = lexer.Token{TokenType: lexer.Punctuation, Val: "("}
-	closeParen = lexer.Token{TokenType: lexer.Punctuation, Val: ")"}
-	openCurly  = lexer.Token{TokenType: lexer.Punctuation, Val: "{"}
-	closeCurly = lexer.Token{TokenType: lexer.Punctuation, Val: "}"}
+	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: ","}
 	pipe       = lexer.Token{TokenType: lexer.Punctuation, Val: "|"}
 	arrow      = lexer.Token{TokenType: lexer.Punctuation, Val: ">"}
@@ -457,6 +457,9 @@ func parseTuple(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
 	if len(toks) < 2 {
 		return rootTup, toks, nil
 	} else if !toks[0].Equal(comma) {
+		if toks[0].TokenType == lexer.Punctuation {
+			return parseConnectingPunct(toks, rootTup)
+		}
 		return rootTup, toks, nil
 	}
 
@@ -479,6 +482,9 @@ func parsePipe(toks []lexer.Token, root Expr) (Expr, []lexer.Token, error) {
 	if len(toks) < 2 {
 		return rootTup, toks, nil
 	} else if !toks[0].Equal(pipe) {
+		if toks[0].TokenType == lexer.Punctuation {
+			return parseConnectingPunct(toks, rootTup)
+		}
 		return rootTup, toks, nil
 	}
 

expr/expr_test.go

@@ -111,6 +111,10 @@ func TestParsePipe(t *T) {
 
 	toks = []lexer.Token{foo, pipe, openParen, foo, pipe, foo, closeParen, pipe, foo, foo}
 	assertParse(t, toks, mkPipe(fooExpr, mkPipe(fooExpr, fooExpr), fooExpr), []lexer.Token{foo})
+
+	fooTupExpr := Tuple{exprs: []Expr{fooExpr, fooExpr}}
+	toks = []lexer.Token{foo, comma, foo, pipe, foo}
+	assertParse(t, toks, mkPipe(fooTupExpr, fooExpr), []lexer.Token{})
 }
 
 func TestParseStatement(t *T) {
@@ -148,6 +152,12 @@ func TestParseStatement(t *T) {
 	fooTupExpr := Tuple{exprs: []Expr{fooExpr, fooExpr}}
 	toks = []lexer.Token{foo, arrow, openParen, foo, comma, foo, closeParen, pipe, foo, foo}
 	assertParse(t, toks, stmt(fooExpr, fooTupExpr, fooExpr), []lexer.Token{foo})
+
+	toks = []lexer.Token{foo, comma, foo, arrow, foo}
+	assertParse(t, toks, stmt(fooTupExpr, fooExpr), []lexer.Token{})
+
+	toks = []lexer.Token{openParen, foo, comma, foo, closeParen, arrow, foo}
+	assertParse(t, toks, stmt(fooTupExpr, fooExpr), []lexer.Token{})
 }
 
 func TestParseBlock(t *T) {

lexer/lexer.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"log"
 	"strings"
 )
 
@@ -15,11 +14,16 @@ type TokenType string
 
 // Different token types
 const (
-	Identifier  TokenType = "identifier"
+	Identifier TokenType = "identifier"
+
+	// Punctuation are tokens which connect two other tokens
 	Punctuation TokenType = "punctuation"
-	String      TokenType = "string"
-	Err         TokenType = "err"
-	EOF         TokenType = "eof"
+
+	// Wrapper wraps one or more tokens
+	Wrapper TokenType = "wrapper"
+	String  TokenType = "string"
+	Err     TokenType = "err"
+	EOF     TokenType = "eof"
 )
 
 // Token is a single token which has been read in. All Tokens have a non-empty
@@ -194,8 +198,9 @@ func (l *Lexer) Next() Token {
 // the actual fsm
 
 var whitespaceSet = " \n\r\t\v\f"
-var punctuationSet = ",{}()<>|"
-var identifierSepSet = whitespaceSet + punctuationSet
+var punctuationSet = ",<>|"
+var wrapperSet = "{}()"
+var identifierSepSet = whitespaceSet + punctuationSet + wrapperSet
 
 func lex(l *Lexer) lexerFn {
 	r, err := l.readRune()
@@ -224,6 +229,10 @@ func lexSingleRune(l *Lexer, r rune) lexerFn {
 		l.bufferRune(r)
 		l.emit(Punctuation)
 		return lex
+	case strings.ContainsRune(wrapperSet, r):
+		l.bufferRune(r)
+		l.emit(Wrapper)
+		return lex
 	case r == '"' || r == '\'' || r == '`':
 		canEscape := r != '`'
 		return lexStrStart(l, r, makeLexStr(r, canEscape))
@@ -266,7 +275,6 @@ func lexLineComment(l *Lexer) lexerFn {
 // assumes the starting / has been read already
 func lexBlockComment(l *Lexer) lexerFn {
 	depth := 1
-	log.Printf("in block comment")
 
 	var recurse lexerFn
 	recurse = func(l *Lexer) lexerFn {

lexer/lexer_test.go

@@ -60,16 +60,16 @@ func TestLex(t *T) {
 	assertNext(Identifier, "100", 6, 2)
 	assertNext(Identifier, "1.5", 7, 2)
 	assertNext(Identifier, "1.5e9", 8, 2)
-	assertNext(Punctuation, "(", 24, 2)
+	assertNext(Wrapper, "(", 24, 2)
 	assertNext(Identifier, "punctuation", 24, 3)
 	assertNext(Punctuation, ",", 24, 14)
 	assertNext(Identifier, "is", 24, 15)
-	assertNext(Punctuation, "{", 24, 17)
+	assertNext(Wrapper, "{", 24, 17)
 	assertNext(Identifier, "cool", 24, 18)
-	assertNext(Punctuation, "}", 24, 22)
+	assertNext(Wrapper, "}", 24, 22)
 	assertNext(Punctuation, "<", 24, 23)
 	assertNext(Punctuation, ">", 24, 24)
-	assertNext(Punctuation, ")", 24, 26)
+	assertNext(Wrapper, ")", 24, 26)
 	assertNext(Identifier, "-tab", 25, 2)
 	assertNext(String, `"this is a string"`, 27, 2)
 	assertNext(Punctuation, ",", 27, 20)