From 37198812016cf53ca2b3fb832d8d09d528f81098 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Thu, 6 Oct 2016 17:23:17 +0200
Subject: List notation shortcut (resolves #5)

---
 doc/grammar.tex         |  5 ++++-
 examples/list-test.fusp |  4 ++--
 interpreter/parse.c     | 58 +++++++++++++++++++++++++++++++++++--------------
 3 files changed, 48 insertions(+), 19 deletions(-)

diff --git a/doc/grammar.tex b/doc/grammar.tex
index 00e24b8..111cfc8 100644
--- a/doc/grammar.tex
+++ b/doc/grammar.tex
@@ -24,8 +24,11 @@
 		\alt <Simple-list>
 		\alt <Simple-tuple>
 
-	<Simple-list> ::= `[' <Simple-expr> `:' <Simple-list> `]'
+	<Simple-list> ::= `[' <Simple-expr-list> `:' <Simple-list> `]'
+		\alt `[' <Simple-expr-list> `]'
 		\alt `[]'
+
+	<Simple-expr-list> ::= <Simple-expr> `,' <Simple-expr-list> | <Simple-expr>
 	
 	<Simple-tuple> ::= `(' <Simple-expr> `,' <Simple-expr> `)'
 
diff --git a/examples/list-test.fusp b/examples/list-test.fusp
index d90a252..f4b5755 100644
--- a/examples/list-test.fusp
+++ b/examples/list-test.fusp
@@ -1,4 +1,4 @@
 import list;
 
-main = flatten [[1:[2:[3:[]]]]:[[4:[5:[6:[]]]]:[]]];
-main = append [1:[2:[3:[]]]] [4:[5:[6:[]]]];
+main = append [1,2,3] [4,5,6];
+main = flatten [[1,2,3],[4,5,6]];
diff --git a/interpreter/parse.c b/interpreter/parse.c
index e0953d1..bdfd968 100644
--- a/interpreter/parse.c
+++ b/interpreter/parse.c
@@ -156,7 +156,6 @@ token_list* parse_expression_no_app(expression* expr, token_list* list) {
 			free_expression(expr);
 		}
 	} else if (list->elem.kind == TOKEN_OPEN_SQ) {
-		expression *expr1, *expr2;
 		token_list* _list;
 
 		expr->kind = EXPR_LIST;
@@ -165,24 +164,51 @@ token_list* parse_expression_no_app(expression* expr, token_list* list) {
 			return list->rest->rest;
 		}
 
-		expr1 = my_calloc(1, sizeof(expression));
-		expr2 = my_calloc(1, sizeof(expression));
+		expr->var1 = my_calloc(1, sizeof(expression));
+		expr->var2 = my_calloc(1, sizeof(expression));
 
-		_list = parse_expression(expr1, list->rest);
-		if (!_list || _list->elem.kind != TOKEN_COLON) {
-			free_expression(expr1);
-			my_free(expr1);
-			my_free(expr2);
-		} else {
-			_list = parse_expression(expr2, _list->rest);
+		_list = parse_expression(expr->var1, list->rest);
+		if (!_list ||
+				(_list->elem.kind != TOKEN_COLON &&
+				 _list->elem.kind != TOKEN_COMMA &&
+				 _list->elem.kind != TOKEN_CLOSE_SQ)) {
+			free_expression(expr);
+		} else if (_list->elem.kind == TOKEN_CLOSE_SQ) {
+			((expression *) expr->var2)->kind = EXPR_LIST;
+			((expression *) expr->var2)->var1 = NULL;
+			((expression *) expr->var2)->var2 = NULL;
+			return _list->rest;
+		} else if (_list->elem.kind == TOKEN_COMMA) {
+			expression* _expr = expr;
+			while (_list && _list->elem.kind == TOKEN_COMMA) {
+				_expr = _expr->var2;
+				_expr->kind = EXPR_LIST;
+				_expr->var1 = my_calloc(1, sizeof(expression));
+				_expr->var2 = my_calloc(1, sizeof(expression));
+				_list = parse_expression(_expr->var1, _list->rest);
+			}
+			if (!_list ||
+					(_list->elem.kind != TOKEN_CLOSE_SQ &&
+					 _list->elem.kind != TOKEN_COLON)) {
+				free_expression(expr);
+			} else if (_list->elem.kind == TOKEN_COLON) {
+				_list = parse_expression(((expression*) expr->var2)->var2, _list->rest);
+				if (!_list || _list->elem.kind != TOKEN_CLOSE_SQ) {
+					free_expression(expr);
+				} else {
+					return _list->rest;
+				}
+			} else if (_list->elem.kind == TOKEN_CLOSE_SQ) {
+				((expression*) _expr->var2)->kind = EXPR_LIST;
+				((expression*) _expr->var2)->var1 = NULL;
+				((expression*) _expr->var2)->var2 = NULL;
+				return _list->rest;
+			}
+		} else if (_list->elem.kind == TOKEN_COLON) {
+			_list = parse_expression(expr->var2, _list->rest);
 			if (!_list || _list->elem.kind != TOKEN_CLOSE_SQ) {
-				free_expression(expr1);
-				free_expression(expr2);
-				my_free(expr1);
-				my_free(expr2);
+				free_expression(expr);
 			} else {
-				expr->var1 = expr1;
-				expr->var2 = expr2;
 				return _list->rest;
 			}
 		}
-- 
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