fix: correct and simplify parsing of expressions.

The expressions were parsed from right to left, and it was incorrect and
cumbersome. Now they are processed from left to right, with a simpler
and correct handling of precedence rules.

The vm function call syntax has been changed to set the function
before the input arguments on the stack, as to follow the declaring
order in languages.

1 files changed, 7 insertions, 7 deletions

diff --git a/parser/parse.go b/parser/parse.go
index e7d5399..60311dc 100644
--- a/parser/parse.go
+++ b/parser/parse.go
@@ -143,7 +143,7 @@ func (p *Parser) parseStmt(in Tokens) (out Tokens, err error) {
 		}
 		fallthrough
 	default:
-		return p.parseExpr(in)
+		return p.parseExpr(in, "")
 	}
 }
 
@@ -220,7 +220,7 @@ func (p *Parser) parseFor(in Tokens) (out Tokens, err error) {
 	}
 	out = append(out, scanner.Token{Tok: lang.Label, Str: p.scope + "b"})
 	if len(cond) > 0 {
-		if cond, err = p.parseExpr(cond); err != nil {
+		if cond, err = p.parseExpr(cond, ""); err != nil {
 			return nil, err
 		}
 		out = append(out, cond...)
@@ -353,7 +353,7 @@ func (p *Parser) parseIf(in Tokens) (out Tokens, err error) {
 			}
 			pre = append(pre, init...)
 		}
-		if cond, err = p.parseExpr(cond); err != nil {
+		if cond, err = p.parseExpr(cond, ""); err != nil {
 			return nil, err
 		}
 		pre = append(pre, cond...)
@@ -393,7 +393,7 @@ func (p *Parser) parseSwitch(in Tokens) (out Tokens, err error) {
 	}
 	condSwitch := false
 	if len(cond) > 0 {
-		if cond, err = p.parseExpr(cond); err != nil {
+		if cond, err = p.parseExpr(cond, ""); err != nil {
 			return nil, err
 		}
 		out = append(out, cond...)
@@ -436,7 +436,7 @@ func (p *Parser) parseCaseClause(in Tokens, index, maximum int, condSwitch bool)
 	}
 	lcond := conds.Split(lang.Comma)
 	for i, cond := range lcond {
-		if cond, err = p.parseExpr(cond); err != nil {
+		if cond, err = p.parseExpr(cond, ""); err != nil {
 			return out, err
 		}
 		txt := fmt.Sprintf("%sc%d.%d", p.scope, index, i)
@@ -472,7 +472,7 @@ func (p *Parser) parseLabel(in Tokens) (out Tokens, err error) {
 
 func (p *Parser) parseReturn(in Tokens) (out Tokens, err error) {
 	if l := len(in); l > 1 {
-		if out, err = p.parseExpr(in[1:]); err != nil {
+		if out, err = p.parseExpr(in[1:], ""); err != nil {
 			return out, err
 		}
 	} else if l == 0 {
@@ -519,5 +519,5 @@ func (p *Parser) popScope() {
 }
 
 func (p *Parser) precedence(t scanner.Token) int {
-	return p.TokenProps[t.Str].Precedence
+	return p.TokenProps[t.Tok].Precedence
 }