From e12e83921b285bb3e2d4a14dcb2fd55697ef1fed Mon Sep 17 00:00:00 2001
From: Sasha Koshka <sashakoshka@tebibyte.media>
Date: Sat, 6 Apr 2024 14:01:14 -0400
Subject: [PATCH] Parse constant access unit specifiers

---
 parser/fspl/expression.go  | 27 +++++++++++++++++++--------
 parser/fspl/parser_test.go |  3 ++-
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/parser/fspl/expression.go b/parser/fspl/expression.go
index 18467af..15ee335 100644
--- a/parser/fspl/expression.go
+++ b/parser/fspl/expression.go
@@ -97,7 +97,7 @@ func (this *treeParser) parseExpressionRoot () (entity.Expression, error) {
 	
 	switch this.Kind() {
 	case lexer.Ident:     return this.parseExpressionRootIdent()
-	case lexer.TypeIdent: return this.parseConstant()
+	case lexer.TypeIdent: return this.parseConstantCore(this.Pos(), "")
 	case lexer.LParen:    return this.parseExpressionRootLParen()
 	case lexer.LBracket:  return this.parseExpressionRootLBracket()
 	case lexer.LBrace:    return this.parseBlock()
@@ -129,11 +129,19 @@ func (this *treeParser) parseExpressionRootIdent () (entity.Expression, error) {
 			// Colon: declaration
 			return this.parseDeclarationCore(pos, name)
 		case lexer.DoubleColon:
-			// DoubleColon: call
-			err := this.ExpectNext(lexer.LBracket)
+			// DoubleColon: call, constant
+			err := this.ExpectNext(lexer.LBracket, lexer.TypeIdent)
 			if err != nil { return nil, err }
-			this.Next()
-			return this.parseCallCore(pos, name)
+
+			switch this.Kind() {
+			case lexer.TypeIdent:
+				// TypeIdent: constant
+				return this.parseConstantCore(pos, name)
+			case lexer.LBracket:
+				// LBracket: call
+				this.Next()
+				return this.parseCallCore(pos, name)
+			}
 		default:
 			// *: variable
 			return &entity.Variable {
@@ -142,6 +150,7 @@ func (this *treeParser) parseExpressionRootIdent () (entity.Expression, error) {
 			}, nil
 		}
 	}
+	panic(this.bug())
 }
 
 func (this *treeParser) parseExpressionRootLParen () (entity.Expression, error) {
@@ -719,12 +728,14 @@ func (this *treeParser) parseFor () (*entity.For, error) {
 	return loop, nil
 }
 
-func (this *treeParser) parseConstant () (*entity.Constant, error) {
+func (this *treeParser) parseConstantCore (pos errors.Position, unitNickname string) (*entity.Constant, error) {
+	pos = pos.Union(this.Pos())
 	err := this.Expect(lexer.TypeIdent)
 	if err != nil { return nil, err }
 	constant := &entity.Constant {
-		Pos:      this.Pos(),
-		TypeName: this.Value(),
+		Pos:          this.Pos(),
+		UnitNickname: unitNickname,
+		TypeName:     this.Value(),
 	}
 	
 	err = this.ExpectNext(lexer.Dot)
diff --git a/parser/fspl/parser_test.go b/parser/fspl/parser_test.go
index c5aea05..0d18c0c 100644
--- a/parser/fspl/parser_test.go
+++ b/parser/fspl/parser_test.go
@@ -84,7 +84,8 @@ testString (test,
 - [for s:String] = for e:Byte in s [break e]
 - [matchToInt u:(| Int F64)]:Int = match u | u:Int u | u:F64 [~ Int u] * 0
 - [switch x:Int] = switch x | 0 5 | 1 4 | 2 3 * 0
-- [whatFile fd:FD]:String = switch fd | FD.stdin 'in' | FD.stdout 'out' * '?'`,
+- [whatFile fd:FD]:String = switch fd | FD.stdin 'in' | FD.stdout 'out' * '?'
+- [whatFile2 fd:io::FD]:String = switch fd | io::FD.stdin 'in' | io::FD.stdout 'out' * '?'`,
 // input
 `
 [var]          = sdfdf