--- a/Tools__Tag.st	Tue Mar 12 16:45:04 2019 +0100
+++ b/Tools__Tag.st	Tue Mar 12 16:46:16 2019 +0100
@@ -420,8 +420,13 @@
 
 !Tag methodsFor:'tag searching'!
 
-lineNumberIn:someText
-    |pat lnr atStart atEnd|
+lineNumberIn:someStringCollectionOrFilename
+    "search the tag and return the line nr or 0, if not found.
+     search either in the collection of lines or the file's contents.
+     This is called with the contents for small files,
+     but with the fileName for huge ones"
+    
+    |pat lnr atStartOfLine atEndOfLine findFirst|
 
     (lineNumber notNil and:[lineNumber ~~ 0]) ifTrue:[
        ^ lineNumber
@@ -429,7 +434,7 @@
 
     (pat := self pattern) isNil ifTrue:[
         lineNumber := 1.
-      ^ lineNumber
+        ^ lineNumber
     ].
 
     (pat endsWith:';"') ifTrue:[
@@ -445,33 +450,53 @@
 "/        ].
     (pat startsWith:$^) ifTrue:[
         pat := pat copyFrom:2.
-        atStart := true.
+        atStartOfLine := true.
     ].
     (pat endsWith:$$) ifTrue:[
         pat := pat copyButLast.
-        atEnd := true.
+        atEndOfLine := true.
     ].
-    atStart == true ifTrue:[
-        atEnd == true ifTrue:[
-            lnr := someText findFirst:[:line | line = pat].
+
+    "/ search either in the collection of lines or the file's contents
+    findFirst := 
+        [:comparer |
+            someStringCollectionOrFilename isFilename ifTrue:[
+                [:exit |
+                    |lineNr|
+                    lineNr := 1.
+                    someStringCollectionOrFilename readingLinesDo:[:line |
+                        (comparer value:line) ifTrue:[exit value:lineNr].
+                        lineNr := lineNr + 1.
+                    ]
+                ] valueWithExit
+            ] ifFalse:[
+                someStringCollectionOrFilename findFirst:comparer
+            ].    
+        ].
+        
+    atStartOfLine == true ifTrue:[
+        atEndOfLine == true ifTrue:[
+            lnr := findFirst value:[:line | line = pat].
         ] ifFalse:[
-            lnr := someText findFirst:[:line | line startsWith:pat].
+            lnr := findFirst value:[:line | line startsWith:pat].
         ]
     ] ifFalse:[
-        atEnd == true ifTrue:[
-            lnr := someText findFirst:[:line | line endsWith:pat].
+        atEndOfLine == true ifTrue:[
+            lnr := findFirst value:[:line | line endsWith:pat].
         ] ifFalse:[
-            lnr := someText findFirst:[:line | line includesString:pat].
+            lnr := findFirst value:[:line | line includesString:pat].
         ].
     ].
 
     lnr == 0 ifTrue:[
-        lnr := someText findFirst:[:line | line includesString:self label].
+        lnr := findFirst value:[:line | line includesString:self label].
         lnr == 0 ifTrue:[
             lnr := 1.
         ].
     ].
     ^ lnr
+
+    "Modified: / 12-03-2019 / 15:08:32 / Claus Gittinger"
 ! !
 
 !Tag methodsFor:'testing'!