CalculationFunction.m: Replace Mathematica's line-breaking with our own

Mathematica's implementation of line-breaking in CForm sometimes
splits lines in the middle of tokens and adds continuation backslashes
to the end of the split line.  In combination with the indentation
that we apply in Kranc, this can cause the tokens to be broken by
whitespace.  This commit inhibits Mathematica's line breaking and
replaces it with an algorithm which splits lines only on whitespace.

1 files changed, 24 insertions, 1 deletions

diff --git a/Tools/CodeGen/CalculationFunction.m b/Tools/CodeGen/CalculationFunction.m
index 08678ae..5efc32c 100644
--- a/Tools/CodeGen/CalculationFunction.m
+++ b/Tools/CodeGen/CalculationFunction.m
@@ -125,6 +125,27 @@ replaceDerivatives[x_, derivRules_] :=
     replaceCustom = Flatten[derivRules,1];
     x /. replaceStandard];
 
+
+(* Take a string s and break it into separate lines using l as a guide
+   to the line length.  If a word (sequence of non-whitespace
+   characters) is longer than l, do not break it.  Add two spaces of
+   indentation after each line break (this will push the line length
+   over l). Algorithm essentially taken from
+   http://en.wikipedia.org/wiki/Word_wrap *)
+lineBreak[s_, l_] :=
+  Module[{spaceLeft, words, word, i, lineWidth = l, spaceWidth = 1,
+    len},
+   spaceLeft = l;
+   words = StringSplit[s];
+   Do[
+    word = words[[i]];
+    len = StringLength[word];
+    If[len > spaceLeft,
+     words[[i]] = "\n  " <> word;
+     spaceLeft = lineWidth - len,
+     spaceLeft = spaceLeft - (len + spaceWidth)], {i, 1, Length[words]}];
+   Return[StringJoin[Riffle[words, " "]]]];
+
 (* Return a CodeGen block which assigns dest by evaluating expr *)
 assignVariableFromExpression[dest_, expr_] := Module[{tSym, type, cleanExpr, code},
       
@@ -135,7 +156,7 @@ assignVariableFromExpression[dest_, expr_] := Module[{tSym, type, cleanExpr, cod
       cleanExpr = ReplacePowers[expr] /. sym`t -> tSym;
   
       If[SOURCELANGUAGE == "C",
-        code = type <> " const " <> ToString[dest] <> " = " <> ToString[cleanExpr, CForm,       PageWidth -> 120] <> ";\n",
+        code = type <> " const " <> ToString[dest] <> " = " <> ToString[cleanExpr, CForm,       PageWidth -> Infinity] <> ";\n",
         code = ToString@dest <> ".eq." <> ToString[cleanExpr, FortranForm, PageWidth -> 120] <> "\n"
        ];
  
@@ -150,6 +171,8 @@ assignVariableFromExpression[dest_, expr_] := Module[{tSym, type, cleanExpr, cod
          ];
       ];
 
+      code = lineBreak[code, 70] <> "\n";
+
 (*      code = StringReplace[code, "Rule"          -> " = "]; *)
       code = StringReplace[code, "normal1"     -> "normal[0]"];
       code = StringReplace[code, "normal2"     -> "normal[1]"];