From 083912ecea176c54e06db5667f251e902a6de55c Mon Sep 17 00:00:00 2001
From: Adrian Thurston <thurston@complang.org>
Date: Wed, 20 Mar 2013 21:53:13 -0400
Subject: some work on context definitions

---
 colm/colm.lm | 21 ++++++++++++++++++++-
 colm/load.cc | 53 +++++++++++++++++++++++++++++++++++++++++++++--------
 colm/load.h  |  8 ++++++--
 3 files changed, 71 insertions(+), 11 deletions(-)

diff --git a/colm/colm.lm b/colm/colm.lm
index b6610fa6..f58f3510 100644
--- a/colm/colm.lm
+++ b/colm/colm.lm
@@ -15,6 +15,7 @@ lex
 	token IN / 'in' /
 
 	token LITERAL /'literal'/
+	token CONTEXT /'context'/
 	token NI /'ni'/
 
 	token NIL / 'nil' /
@@ -107,7 +108,7 @@ def root_item
 |	[IgnoreDef: ignore_def]
 |	[CflDef: cfl_def]
 |	[RegionDef: region_def]
-#|	[context_def]
+|	[ContextDef: context_def]
 |	[NamespaceDef: namespace_def]
 #|	[function_def]
 #|	[iter_def]
@@ -118,6 +119,24 @@ def root_item
 #|	[precedence]
 #|	[typedef]
 
+def context_item
+#	[context_var_def]
+	[LiteralDef: literal_def]
+#|	[rl_def]
+|	[TokenDef: token_def]
+|	[IgnoreDef: ignore_def]
+|	[CflDef: cfl_def]
+|	[RegionDef: region_def]
+|	[ContextDef: context_def]
+#|	[function_def]
+#|	[iter_def]
+#|	[export_def]
+#|	[pre_eof]
+#|	[precedence]
+
+def context_def
+	[CONTEXT Name: id ContextItemList: context_item* END]
+
 def literal_def
 	[LITERAL LiteralList: literal_list]
 
diff --git a/colm/load.cc b/colm/load.cc
index 6f1973d8..f11a76b0 100644
--- a/colm/load.cc
+++ b/colm/load.cc
@@ -366,14 +366,14 @@ void LoadSource::walkIgnoreDef( ignore_def IgnoreDef )
 	defineToken( internal, 0, join, objectDef, 0, true, false, false );
 }
 
-void LoadSource::walkLexRegion( region_def &regionDef )
+void LoadSource::walkLexRegion( region_def regionDef )
 {
 	pushRegionSet( internal );
 	walkRootItemList( regionDef.RootItemList() );
 	popRegionSet();
 }
 
-void LoadSource::walkCflDef( cfl_def &cflDef )
+void LoadSource::walkCflDef( cfl_def cflDef )
 {
 	prod_list prodList = cflDef.ProdList();
 
@@ -622,6 +622,43 @@ LangStmt *LoadSource::walkStatement( statement Statement )
 	return stmt;
 }
 
+void LoadSource::walkContextItem( context_item contextItem )
+{
+	if ( contextItem.TokenDef() != 0 ) {
+		walkTokenDef( contextItem.TokenDef() );
+	}
+	else if ( contextItem.IgnoreDef() != 0 ) {
+		walkIgnoreDef( contextItem.IgnoreDef() );
+	}
+	else if ( contextItem.LiteralDef() != 0 ) {
+		walkLiteralDef( contextItem.LiteralDef() );
+	}
+	else if ( contextItem.CflDef() != 0 ) {
+		walkCflDef( contextItem.CflDef() );
+	}
+	else if ( contextItem.RegionDef() != 0 ) {
+		walkLexRegion( contextItem.RegionDef() );
+	}
+	else if ( contextItem.ContextDef() != 0 ) {
+		walkContextDef( contextItem.ContextDef() );
+	}
+}
+
+void LoadSource::walkContextDef( context_def contextDef )
+{
+	String name = contextDef.Name().text().c_str();
+	contextHead( internal, name );
+
+	_repeat_context_item contextItemList = contextDef.ContextItemList();
+	while ( !contextItemList.end() ) {
+		walkContextItem( contextItemList.value() );
+		contextItemList = contextItemList.next();
+	}
+
+	contextStack.pop();
+	namespaceStack.pop();
+}
+
 void LoadSource::walkNamespaceDef( namespace_def NamespaceDef )
 {
 	String name = NamespaceDef.Name().text().c_str();
@@ -642,19 +679,19 @@ void LoadSource::walkRootItem( root_item &rootItem, StmtList *stmtList )
 		walkLiteralDef( rootItem.LiteralDef() );
 	}
 	else if ( rootItem.CflDef() != 0 ) {
-		cfl_def cflDef = rootItem.CflDef();
-		walkCflDef( cflDef );
+		walkCflDef( rootItem.CflDef() );
 	}
 	else if ( rootItem.RegionDef() != 0 ) {
-		region_def regionDef = rootItem.RegionDef();
-		walkLexRegion( regionDef );
+		walkLexRegion( rootItem.RegionDef() );
 	}
 	else if ( rootItem.Statement() != 0 ) {
-		statement Statement = rootItem.Statement();
-		LangStmt *stmt = walkStatement( Statement );
+		LangStmt *stmt = walkStatement( rootItem.Statement() );
 		if ( stmt != 0 )
 			stmtList->append( stmt );
 	}
+	else if ( rootItem.ContextDef() != 0 ) {
+		walkContextDef( rootItem.ContextDef() );
+	}
 	else if ( rootItem.NamespaceDef() != 0 ) {
 		walkNamespaceDef( rootItem.NamespaceDef() );
 	}
diff --git a/colm/load.h b/colm/load.h
index 77ecb8c1..d75c2b21 100644
--- a/colm/load.h
+++ b/colm/load.h
@@ -63,6 +63,8 @@ struct literal_list;
 struct literal_def;
 struct token_def;
 struct ignore_def;
+struct context_def;
+struct context_item;
 
 struct LoadSource
 :
@@ -93,10 +95,10 @@ struct LoadSource
 	ExprVect *walkCodeExprList( _repeat_code_expr codeExprList );
 	LangExpr *walkCodeExpr( code_expr codeExpr );
 	void walkTokenList( token_list &TokenList );
-	void walkLexRegion( region_def &regionDef );
+	void walkLexRegion( region_def regionDef );
 	void walkProdElList( ProdElList *list, prod_el_list &ProdElList );
 	void walkProdList( LelDefList *lelDefList, prod_list &ProdList );
-	void walkCflDef( cfl_def &cflDef );
+	void walkCflDef( cfl_def cflDef );
 	LangTerm *walkIterCall( iter_call IterCall );
 	LangStmt *walkOptionalElse( optional_else optionalElse );
 	LangStmt *walkElsifClause( elsif_clause elsifClause );
@@ -119,6 +121,8 @@ struct LoadSource
 
 	void walkTokenDef( token_def TokenDef );
 	void walkIgnoreDef( ignore_def IgnoreDef );
+	void walkContextDef( context_def contextDef );
+	void walkContextItem( context_item contextItem );
 
 	void go();
 };
-- 
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