colm: added outdent check on literal concatenations

The colm language has an ambiguity between literal concatenations and distinct
statements, where the first ends in string/accum/cons/pat and the second is a
bare send. For example:

match P
	"a b c d"
"e f g h"

Warn on some of these by checking for an outdent (relative to the first
component) on top level concatenations. If the user does not outdent between
separate intended statements we cannot help with this check.

refs #95

2 files changed, 97 insertions, 45 deletions

diff --git a/colm/loadfinal.cc b/colm/loadfinal.cc
index 6c8eb847..0fddd360 100644
--- a/colm/loadfinal.cc
+++ b/colm/loadfinal.cc
@@ -88,6 +88,41 @@ struct LoadColm
 
 	const char *inputFileName;
 
+	struct Alignment
+	{
+		Alignment()
+		:
+			firstLine(0),
+			lastLine(0),
+			firstColumn(0)
+		{}
+
+		int firstLine;
+		int lastLine;
+		int firstColumn;
+
+		void check( const char *type, colm_location *loc )
+		{
+			if ( firstLine == 0 ) {
+				firstLine = lastLine = loc->line;
+				firstColumn = loc->column;
+			}
+			else {
+				/* Checking if we are outdented. Indents and are ok. So is
+				 * outdenting back to the first. */
+				if ( loc->column < firstColumn ) {
+					warning( loc ) << type << " literal outdented beyond first at " <<
+							firstLine << ":" << firstColumn <<
+							", possible unintended concatenation" << std::endl;
+				}
+
+				lastLine = loc->line;
+			}
+		}
+	};
+	
+
+
 	Literal *walkLexRangeLit( lex_range_lit lexRangeLit )
 	{
 		Literal *literal = 0;
@@ -550,8 +585,8 @@ struct LoadColm
 			String nl = unescape( Nl.data() );
 			PatternItem *patternItem = PatternItem::cons( PatternItem::InputTextForm,
 					Nl.loc(), nl );
-			PatternItemList *term = PatternItemList::cons( patternItem );
-			list = patListConcat( list, term );
+			PatternItemList *tail = PatternItemList::cons( patternItem );
+			list = patListConcat( list, tail );
 		}
 
 		return list;
@@ -577,8 +612,8 @@ struct LoadColm
 			String nl = unescape( Nl.data() );
 			ConsItem *consItem = ConsItem::cons(
 					Nl.loc(), ConsItem::InputText, nl );
-			ConsItemList *term = ConsItemList::cons( consItem );
-			list = consListConcat( list, term );
+			ConsItemList *tail = ConsItemList::cons( consItem );
+			list = consListConcat( list, tail );
 		}
 
 		return list;
@@ -601,8 +636,8 @@ struct LoadColm
 			String nl = unescape( Nl.data() );
 			PatternItem *patternItem = PatternItem::cons( PatternItem::InputTextForm,
 					Nl.loc(), nl );
-			PatternItemList *term = PatternItemList::cons( patternItem );
-			list = patListConcat( list, term );
+			PatternItemList *tail = PatternItemList::cons( patternItem );
+			list = patListConcat( list, tail );
 		}
 
 		return list;
@@ -651,15 +686,18 @@ struct LoadColm
 
 	PatternItemList *walkPatternList( pattern_list patternList, LangVarRef *patternVarRef )
 	{
-		PatternItemList *ret = new PatternItemList;
+		Alignment alignment;
+		PatternItemList *list = new PatternItemList;
 		RepeatIter<pattern_top_el> patternTopElIter ( patternList );
 		while ( !patternTopElIter.end() ) {
-			PatternItemList *list = walkPattternTopEl( patternTopElIter.value(), patternVarRef );
-			ret->append( *list );
-			delete list;
+			pattern_top_el topEl = patternTopElIter.value();
+			alignment.check( "pattern", topEl.loc() );
+
+			PatternItemList *tail = walkPattternTopEl( topEl, patternVarRef );
+			list = patListConcat( list, tail );
 			patternTopElIter.next();
 		}
-		return ret;
+		return list;
 	}
 
 	PatternItemList *walkPattern( pattern Pattern, LangVarRef *patternVarRef )
@@ -1470,18 +1508,17 @@ struct LoadColm
 		ConsItemList *list = new ConsItemList;
 
 		RepeatIter<lit_cons_el> litConsElIter( litConsElList );
-
 		while ( !litConsElIter.end() ) {
-			ConsItemList *extension = walkLitConsEl( litConsElIter.value(), consTypeRef );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkLitConsEl( litConsElIter.value(), consTypeRef );
+			list = consListConcat( list, tail );
 			litConsElIter.next();
 		}
 
 		if ( Nl != 0 ) {
 			String consData = unescape( Nl.data() );
 			ConsItem *consItem = ConsItem::cons( Nl.loc(), ConsItem::InputText, consData );
-			ConsItemList *term = ConsItemList::cons( consItem );
-			list = consListConcat( list, term );
+			ConsItemList *tail = ConsItemList::cons( consItem );
+			list = consListConcat( list, tail );
 		}
 
 		return list;
@@ -1533,8 +1570,8 @@ struct LoadColm
 		RepeatIter<cons_el> consElIter( consElList );
 
 		while ( !consElIter.end() ) {
-			ConsItemList *extension = walkConsEl( consElIter.value(), consTypeRef );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkConsEl( consElIter.value(), consTypeRef );
+			list = consListConcat( list, tail );
 			consElIter.next();
 		}
 		return list;
@@ -1567,15 +1604,18 @@ struct LoadColm
 
 	ConsItemList *walkConsList( cons_list consList, TypeRef *consTypeRef )
 	{
-		ConsItemList *ret = new ConsItemList;
+		Alignment alignment;
+		ConsItemList *list = new ConsItemList;
 		RepeatIter<cons_top_el> consTopElIter ( consList );
 		while ( !consTopElIter.end() ) {
-			ConsItemList *list = walkConsTopEl( consTopElIter.value(), consTypeRef );
-			ret->append( *list );
-			delete list;
+			cons_top_el topEl = consTopElIter.value();
+			alignment.check( "constructor", topEl.loc() );
+
+			ConsItemList *tail = walkConsTopEl( topEl, consTypeRef );
+			list = consListConcat( list, tail );
 			consTopElIter.next();
 		}
-		return ret;
+		return list;
 	}
 
 	ConsItemList *walkConstructor( constructor Constructor, TypeRef *consTypeRef )
@@ -1615,8 +1655,8 @@ struct LoadColm
 		RepeatIter<lit_string_el> litStringElIter( litStringElList );
 
 		while ( !litStringElIter.end() ) {
-			ConsItemList *extension = walkLitStringEl( litStringElIter.value() );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkLitStringEl( litStringElIter.value() );
+			list = consListConcat( list, tail );
 			litStringElIter.next();
 		}
 
@@ -1624,8 +1664,8 @@ struct LoadColm
 			String consData = unescape( Nl.data() );
 			ConsItem *consItem = ConsItem::cons( Nl.loc(),
 					ConsItem::InputText, consData );
-			ConsItemList *term = ConsItemList::cons( consItem );
-			list = consListConcat( list, term );
+			ConsItemList *tail = ConsItemList::cons( consItem );
+			list = consListConcat( list, tail );
 		}
 		return list;
 	}
@@ -1671,8 +1711,8 @@ struct LoadColm
 		RepeatIter<string_el> stringElIter( stringElList );
 
 		while ( !stringElIter.end() ) {
-			ConsItemList *extension = walkStringEl( stringElIter.value() );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkStringEl( stringElIter.value() );
+			list = consListConcat( list, tail );
 			stringElIter.next();
 		}
 		return list;
@@ -1705,15 +1745,18 @@ struct LoadColm
 
 	ConsItemList *walkStringList( string_list stringList )
 	{
-		ConsItemList *ret = new ConsItemList;
+		Alignment alignment;
+		ConsItemList *list = new ConsItemList;
 		RepeatIter<string_top_el> stringTopElIter( stringList );
 		while ( !stringTopElIter.end() ) {
-			ConsItemList *list = walkStringTopEl( stringTopElIter.value() );
-			ret->append( *list );
-			delete list;
+			string_top_el topEl = stringTopElIter.value();
+			alignment.check( "string", topEl.loc() );
+
+			ConsItemList *tail = walkStringTopEl( topEl );
+			list = consListConcat( list, tail );
 			stringTopElIter.next();
 		}
-		return ret;
+		return list;
 	}
 
 	ConsItemList *walkString( string String )
@@ -1753,16 +1796,16 @@ struct LoadColm
 		RepeatIter<lit_accum_el> litAccumElIter( litAccumElList );
 
 		while ( !litAccumElIter.end() ) {
-			ConsItemList *extension = walkLitAccumEl( litAccumElIter.value() );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkLitAccumEl( litAccumElIter.value() );
+			list = consListConcat( list, tail );
 			litAccumElIter.next();
 		}
 
 		if ( Nl != 0 ) {
 			String consData = unescape( Nl.data() );
 			ConsItem *consItem = ConsItem::cons( Nl.loc(), ConsItem::InputText, consData );
-			ConsItemList *term = ConsItemList::cons( consItem );
-			list = consListConcat( list, term );
+			ConsItemList *tail = ConsItemList::cons( consItem );
+			list = consListConcat( list, tail );
 		}
 
 		return list;
@@ -1809,8 +1852,8 @@ struct LoadColm
 		RepeatIter<accum_el> accumElIter( accumElList );
 
 		while ( !accumElIter.end() ) {
-			ConsItemList *extension = walkAccumEl( accumElIter.value() );
-			list = consListConcat( list, extension );
+			ConsItemList *tail = walkAccumEl( accumElIter.value() );
+			list = consListConcat( list, tail );
 			accumElIter.next();
 		}
 		return list;
@@ -1845,13 +1888,15 @@ struct LoadColm
 		return list;
 	}
 
-	ConsItemList *walkAccumList( accum_list accumList )
+	ConsItemList *walkAccumList( Alignment &alignment, accum_list accumList )
 	{
-		ConsItemList *list = walkAccumTopEl( accumList.accum_top_el() );
+		accum_top_el topEl = accumList.accum_top_el();
+		alignment.check( "accumulator", topEl.loc() );
 
+		ConsItemList *list = walkAccumTopEl( topEl  );
 		if ( accumList.prodName() == accum_list::List ) {
-			ConsItemList *extension = walkAccumList( accumList._accum_list() );
-			consListConcat( list, extension );
+			ConsItemList *tail = walkAccumList( alignment, accumList._accum_list() );
+			list = consListConcat( list, tail );
 		}
 
 		return list;
@@ -1859,7 +1904,8 @@ struct LoadColm
 
 	ConsItemList *walkAccumulate( accumulate Accumulate )
 	{
-		ConsItemList *list = walkAccumList( Accumulate.accum_list() );
+		Alignment alignment;
+		ConsItemList *list = walkAccumList( alignment, Accumulate.accum_list() );
 		return list;
 	}
 
diff --git a/colm/parser.cc b/colm/parser.cc
index 23e60ec2..a41288b1 100644
--- a/colm/parser.cc
+++ b/colm/parser.cc
@@ -829,6 +829,9 @@ ProdElList *BaseParser::appendProdEl( ProdElList *prodElList, ProdEl *prodEl )
 PatternItemList *BaseParser::patListConcat( PatternItemList *list1,
 		PatternItemList *list2 )
 {
+	if ( list1 == 0 )
+		list1 = new PatternItemList();
+		
 	list1->append( *list2 );
 	delete list2;
 	return list1;
@@ -837,6 +840,9 @@ PatternItemList *BaseParser::patListConcat( PatternItemList *list1,
 ConsItemList *BaseParser::consListConcat( ConsItemList *list1,
 		ConsItemList *list2 )
 {
+	if ( list1 == 0 )
+		list1 = new ConsItemList();
+
 	list1->append( *list2 );
 	delete list2;
 	return list1;