Remove srcSpanStartLine/srcSpanEndLine crash

[ghc-hetmet.git] / compiler / basicTypes / SrcLoc.lhs

diff --git a/compiler/basicTypes/SrcLoc.lhs b/compiler/basicTypes/SrcLoc.lhs
index 51d4318..8ced456 100644 (file)
--- a/compiler/basicTypes/SrcLoc.lhs
+++ b/compiler/basicTypes/SrcLoc.lhs
@@ -26,16 +26,17 @@ module SrcLoc (
        pprDefnLoc,
 
        SrcSpan,                -- Abstract
-       noSrcSpan,
+       noSrcSpan, 
        mkGeneralSrcSpan, 
-       isGoodSrcSpan,
+       isGoodSrcSpan, isOneLineSpan,
        mkSrcSpan, srcLocSpan,
        combineSrcSpans,
-       srcSpanFile,
-       srcSpanStartLine, srcSpanEndLine,
-       srcSpanStartCol, srcSpanEndCol,
        srcSpanStart, srcSpanEnd,
 
+       -- These are dubious exports, because they crash on some inputs,
+       -- used only in Lexer.x where we are sure what the Span looks like
+       srcSpanFile, srcSpanEndLine, srcSpanEndCol,
+
        Located(..), getLoc, unLoc, noLoc, eqLocated, cmpLocated, combineLocs, addCLoc
     ) where
 
@@ -222,6 +223,19 @@ isGoodSrcSpan SrcSpanMultiLine{} = True
 isGoodSrcSpan SrcSpanPoint{} = True
 isGoodSrcSpan _ = False
 
+isOneLineSpan :: SrcSpan -> Bool
+-- True if the span is known to straddle more than one line
+-- By default, it returns False
+isOneLineSpan s
+  | isGoodSrcSpan s = srcSpanStartLine s == srcSpanEndLine s
+  | otherwise      = False             
+
+--------------------------------------------------------
+-- Don't export these four;
+-- they panic on Imported, Unhelpful.
+-- They are for internal use only
+-- Urk!  Some are needed for Lexer.x; see comment in export list
+
 srcSpanStartLine SrcSpanOneLine{ srcSpanLine=l } = l
 srcSpanStartLine SrcSpanMultiLine{ srcSpanSLine=l } = l
 srcSpanStartLine SrcSpanPoint{ srcSpanLine=l } = l
@@ -241,13 +255,13 @@ srcSpanEndCol SrcSpanOneLine{ srcSpanECol=c } = c
 srcSpanEndCol SrcSpanMultiLine{ srcSpanECol=c } = c
 srcSpanEndCol SrcSpanPoint{ srcSpanCol=c } = c
 srcSpanEndCol _ = panic "SrcLoc.srcSpanEndCol"
+--------------------------------------------------------
 
 srcSpanStart (ImportedSpan str) = ImportedLoc str
 srcSpanStart (UnhelpfulSpan str) = UnhelpfulLoc str
-srcSpanStart s = 
-  mkSrcLoc (srcSpanFile s) 
-          (srcSpanStartLine s)
-          (srcSpanStartCol s)
+srcSpanStart s = mkSrcLoc (srcSpanFile s) 
+                         (srcSpanStartLine s)
+                         (srcSpanStartCol s)
 
 srcSpanEnd (ImportedSpan str) = ImportedLoc str
 srcSpanEnd (UnhelpfulSpan str) = UnhelpfulLoc str