From 4ef51410999ebcd12b967ba4228659f57650d956 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Tue, 7 Mar 2017 15:50:27 +0100
Subject: Tuple constructors (resolves #2)

---
 README.md          | 11 +++++++++++
 frontend/parse.icl | 23 +++++++++++++----------
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 3c02a28..d6dd1a9 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ This is a fork to implement experimental new features.
 
 1\. [Syntactic sugar](#1-syntactic-sugar)  
 1.1. [Lambda-case](#11-lambda-case)  
+1.2. [Tuple constructors](#12-tuple-constructors)  
 2\. [Syntax changes](#2-syntax-changes)  
 2.1. [Use of module header keywords](#21-use-of-module-header-keywords)  
 
@@ -50,6 +51,16 @@ LambdaAbstr = ...
             | \case of {CaseAltDef}+
 ```
 
+### 1.2. Tuple constructors
+
+There are now tuple constructors that can be used curriedly, similar to GHC and
+the way the tuple type could be curried already. For example:
+
+```clean
+import StdFunc
+Start = flip (,) 5 10
+```
+
 ## 2. Syntax changes
 
 ### 2.1. Use of module header keywords
diff --git a/frontend/parse.icl b/frontend/parse.icl
index 95e7b9d..85e3364 100644
--- a/frontend/parse.icl
+++ b/frontend/parse.icl
@@ -3020,18 +3020,9 @@ trySimpleTypeT token attr pState
 
 trySimpleTypeT_after_OpenToken :: !Token !TypeAttribute !ParseState -> (!ParseResult, !AType, !ParseState)
 trySimpleTypeT_after_OpenToken CommaToken attr pState
-	# (tup_arity, pState)		= determine_arity_of_tuple 2 pState
+	# (tup_arity, pState)		= determine_arity_of_tuple "tuple type" 2 pState
 	  tuple_symbol = makeTupleTypeSymbol tup_arity 0
 	= (ParseOk, {at_attribute = attr, at_type = TA tuple_symbol []}, pState)	
-  where
-	determine_arity_of_tuple :: !Int !ParseState -> (!Int, !ParseState)
-	determine_arity_of_tuple arity pState
-		# (token, pState) = nextToken TypeContext pState
-		| CommaToken == token
-  			= determine_arity_of_tuple (inc arity) pState
-		| CloseToken == token
-			= (arity, pState)
-			= (arity, parseError "tuple type" (Yes token) ")" pState)
 trySimpleTypeT_after_OpenToken ArrowToken attr pState
 	# (token, pState) = nextToken TypeContext pState
 	| token == CloseToken
@@ -3062,6 +3053,15 @@ trySimpleTypeT_after_OpenToken_and_type CommaToken annot_with_pos atype attr pSt
 trySimpleTypeT_after_OpenToken_and_type token annot_with_pos atype attr pState
 	= (ParseFailWithError, atype, parseError "Simple type" (Yes token) "')' or ','" pState)
 
+determine_arity_of_tuple :: !String !Int !ParseState -> (!Int, !ParseState)
+determine_arity_of_tuple error arity pState
+	# (token, pState) = nextToken TypeContext pState
+	| CommaToken == token
+		= determine_arity_of_tuple error (inc arity) pState
+	| CloseToken == token
+		= (arity, pState)
+		= (arity, parseError error (Yes token) ")" pState)
+
 instance try BasicType
 where
 	try IntTypeToken	 pState = (Yes BT_Int			, pState)
@@ -3592,6 +3592,9 @@ trySimpleExpressionT OpenToken pState
 		CloseToken
 			#! unit_cons_ident = predefined_idents.[PD_UnitConsSymbol]
 			-> (True,PE_Ident unit_cons_ident,pState)
+		CommaToken
+			#! (tup_arity, pState) = determine_arity_of_tuple "tuple constructor" 2 pState
+			-> (True, PE_Ident predefined_idents.[GetTupleConsIndex tup_arity], pState)
 		_
 			# (args=:[exp:exps], pState) = want_expression_list_t token pState
 			  pState = wantToken FunctionContext "expression list" CloseToken pState
-- 
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