fix: handle assign statements on map elements

A new token MapAssign is added to implement assignements involving
a map, slice or array, an index key expression and a value expression.

3 files changed, 10 insertions, 2 deletions

diff --git a/parser/README.md b/parser/README.md
index 9f40e77..ccf580d 100644
--- a/parser/README.md
+++ b/parser/README.md
@@ -59,6 +59,7 @@ Go language support:
 - [x] iota expression
 - [ ] defer statement
 - [ ] recover statement
+- [ ] range clause
 - [ ] go statement
 - [x] if statement (including else and else if)
 - [x] for statement
diff --git a/parser/expr.go b/parser/expr.go
index 0a87999..35e54ff 100644
--- a/parser/expr.go
+++ b/parser/expr.go
@@ -145,7 +145,14 @@ func (p *Parser) parseExpr(in Tokens, typeStr string) (out Tokens, err error) {
 				return out, err
 			}
 			out = append(out, toks...)
-			ops = append(ops, scanner.Token{Tok: lang.Index, Pos: t.Pos})
+			if i < len(in)-2 && in[i+1].Tok == lang.Assign {
+				// A brace block followed by assign implies a MapAssing token,
+				// as assignement to a map element cannot be implemented through a normal Assign.
+				ops = append(ops, scanner.Token{Tok: lang.MapAssign, Pos: t.Pos})
+				i++
+			} else {
+				ops = append(ops, scanner.Token{Tok: lang.Index, Pos: t.Pos})
+			}
 
 		case lang.Struct:
 			typ, err := p.parseTypeExpr(in[i : i+2])
diff --git a/parser/parse.go b/parser/parse.go
index c049b87..32ee0e3 100644
--- a/parser/parse.go
+++ b/parser/parse.go
@@ -59,7 +59,7 @@ func (p *Parser) Scan(s string, endSemi bool) (Tokens, error) {
 	return p.Scanner.Scan(s, endSemi)
 }
 
-// Parse performs syntax analysis on s and return Tokens or an error.
+// Parse performs syntax analysis on s and returns Tokens or an error.
 func (p *Parser) Parse(src string) (out Tokens, err error) {
 	in, err := p.Scan(src, true)
 	if err != nil {