Implement function calls

4 files changed, 110 insertions, 1 deletions

diff --git a/GRAMMAR.txt b/GRAMMAR.txt
index c687722..9e30c24 100644
--- a/GRAMMAR.txt
+++ b/GRAMMAR.txt
@@ -20,8 +20,10 @@ term -> numeral ( ( "<<" | ">>" ) numeral )*
 numeral -> factor ( ( "+" | "-" ) factor )*
 factor -> unary ( ( "*" | "/" ) unary )*
 unary -> ( "-" | "!" | "~" )? primary
-primary -> grouping | literal
+primary -> grouping | literal | call
 grouping -> "(" expression ")"
 literal -> string | number
 string -> STRING*
 number -> NUMBER IDENTIFIER
+call -> IDENTIFIER "(" arg? ")"
+arg -> expression ( "," arg )?
diff --git a/expression.go b/expression.go
index 6cc6539..c62918c 100644
--- a/expression.go
+++ b/expression.go
@@ -257,3 +257,22 @@ func (g *groupingExpr) markExprExpr() {}
 func (g *groupingExpr) markPrimaryExpr() {}
 
 func (g *groupingExpr) line() int { return g.ln }
+
+type callExpr struct {
+	funcName string
+	args     *argument
+	ln       int
+}
+
+func (c *callExpr) markExpr() {}
+
+func (c *callExpr) markExprExpr() {}
+
+func (c *callExpr) markPrimaryExpr() {}
+
+func (c *callExpr) line() int { return c.ln }
+
+type argument struct {
+	value exprExpr
+	next  *argument
+}
diff --git a/generate.go b/generate.go
index 317e11c..3e21a0c 100644
--- a/generate.go
+++ b/generate.go
@@ -378,3 +378,24 @@ func (n *numberExpr) generate(w io.Writer) (string, error) {
 
 	return fmt.Sprintf("%d", num), nil
 }
+
+func (c *callExpr) generate(w io.Writer) (string, error) {
+	ret := allocReg()
+
+	fmt.Fprintf(w, "%s =w call $%s(", ret, c.funcName)
+
+	delim := ""
+	for arg := c.args; arg != nil; arg = arg.next {
+		reg, err := arg.value.generate(w)
+		if err != nil {
+			return "", err
+		}
+
+		fmt.Fprintf(w, "w %s%s", reg, delim)
+		delim = ","
+	}
+
+	fmt.Fprintf(w, ")\n")
+
+	return ret, nil
+}
diff --git a/parse.go b/parse.go
index 289c205..5261dfe 100644
--- a/parse.go
+++ b/parse.go
@@ -651,6 +651,14 @@ func parsePrimary(toks *tokens) (primaryExpr, error) {
 		return lit, nil
 	}
 
+	call, err := parseCall(toks)
+	if err != nil {
+		return nil, err
+	}
+	if call != nil {
+		return call, nil
+	}
+
 	return nil, expectedPrimary{got: toks.current()}
 }
 
@@ -761,3 +769,62 @@ func parseNumber(toks *tokens) (*numberExpr, error) {
 
 	return &numberExpr{typ: typeTok.value, s: numTok.value, ln: numTok.line}, nil
 }
+
+func parseCall(toks *tokens) (*callExpr, error) {
+	nameTok, ok := toks.consumeToken()
+	if !ok {
+		return nil, unexpectedEOF
+	}
+
+	if nameTok.kind != identifier {
+		toks.unreadToken()
+		return nil, nil
+	}
+
+	if err := toks.mustMatch(lparen); err != nil {
+		return nil, err
+	}
+
+	args, err := parseArg(toks)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := toks.mustMatch(rparen); err != nil {
+		return nil, err
+	}
+
+	return &callExpr{funcName: nameTok.value, args: args, ln: nameTok.line}, nil
+}
+
+func parseArg(toks *tokens) (*argument, error) {
+	ok, err := toks.match(rparen)
+	if err != nil {
+		return nil, err
+	}
+	toks.unreadToken()
+	if ok {
+		return nil, nil
+	}
+
+	arg, err := parseExpression(toks)
+	if err != nil {
+		return nil, err
+	}
+
+	ok, err = toks.match(comma)
+	if err != nil {
+		return nil, err
+	}
+	if !ok {
+		toks.unreadToken()
+		return &argument{value: arg}, nil
+	}
+
+	next, err := parseArg(toks)
+	if err != nil {
+		return nil, err
+	}
+
+	return &argument{value: arg, next: next}, nil
+}