From 4be72cbb24a2fc27915b1375ac444cfb2fce77f0 Mon Sep 17 00:00:00 2001
From: Adam Sampson <ats@offog.org>
Date: Sun, 18 Mar 2007 01:51:41 +0000
Subject: [PATCH] Move indentation parsing out to its own module

---
 fco2/Indentation.hs | 48 ++++++++++++++++++++++++++++++++++++++++++
 fco2/Makefile       |  1 +
 fco2/Parse.hs       | 51 +++++----------------------------------------
 3 files changed, 54 insertions(+), 46 deletions(-)
 create mode 100644 fco2/Indentation.hs

diff --git a/fco2/Indentation.hs b/fco2/Indentation.hs
new file mode 100644
index 0000000..ee9bf56
--- /dev/null
+++ b/fco2/Indentation.hs
@@ -0,0 +1,48 @@
+module Indentation (parseIndentation, indentMarker, outdentMarker, eolMarker) where
+
+import Data.List
+
+-- XXX this doesn't handle multi-line strings
+-- XXX or VALOF processes
+-- XXX or tabs
+
+indentMarker = "__indent"
+outdentMarker = "__outdent"
+eolMarker = "__eol"
+
+countIndent :: String -> Int
+countIndent (' ':' ':cs) = 1 + (countIndent cs)
+countIndent (' ':cs) = error "Bad indentation"
+countIndent _ = 0
+
+stripIndent :: String -> String
+stripIndent (' ':cs) = stripIndent cs
+stripIndent cs = cs
+
+stripComment :: String -> String
+stripComment [] = []
+stripComment ('-':'-':s) = []
+stripComment ('"':s) = '"' : stripCommentInString s
+stripComment (c:s) = c : stripComment s
+
+stripCommentInString :: String -> String
+stripCommentInString [] = error "In string at end of line"
+stripCommentInString ('"':s) = '"' : stripComment s
+stripCommentInString (c:s) = c : stripCommentInString s
+
+parseIndentation :: [String] -> String
+parseIndentation ls = concat $ intersperse "\n" $ lines
+  where
+    (initSuffix, lines) = flatten' ls 0
+    rep n i = concat $ take n (repeat i)
+    flatten' [] level = ("", [rep level (' ' : outdentMarker)])
+    flatten' (s:ss) level
+      | stripped == ""   = let (suffix, rest) = flatten' ss level in ("", suffix : rest)
+      | newLevel > level = (rep (newLevel - level) (' ' : indentMarker), stripped : rest)
+      | newLevel < level = (rep (level - newLevel) (' ' : outdentMarker), stripped : rest)
+      | otherwise        = ("", stripped : rest)
+      where newLevel = countIndent s
+            stripped' = stripComment s
+            stripped = (if stripIndent stripped' == "" then "" else (stripped' ++ (' ' : eolMarker))) ++ suffix
+            (suffix, rest) = flatten' ss newLevel
+
diff --git a/fco2/Makefile b/fco2/Makefile
index 27a8de3..54b4323 100644
--- a/fco2/Makefile
+++ b/fco2/Makefile
@@ -5,6 +5,7 @@ all: $(targets)
 sources = \
 	AST.hs \
 	Errors.hs \
+	Indentation.hs \
 	Main.hs \
 	Metadata.hs \
 	Parse.hs \
diff --git a/fco2/Parse.hs b/fco2/Parse.hs
index 3203660..23065a0 100644
--- a/fco2/Parse.hs
+++ b/fco2/Parse.hs
@@ -14,6 +14,7 @@ import qualified AST as A
 import Metadata
 import ParseState
 import Errors
+import Indentation
 
 --{{{ setup stuff for Parsec
 type OccParser = GenParser Char ParseState
@@ -213,9 +214,9 @@ mainMarker = "__main"
 
 sMainMarker = reserved mainMarker
 
-indent = symbol "__indent"
-outdent = symbol "__outdent"
-eol = symbol "__eol"
+indent = symbol indentMarker
+outdent = symbol outdentMarker
+eol = symbol eolMarker
 --}}}
 
 --{{{ helper functions
@@ -1065,53 +1066,11 @@ sourceFile
 --}}}
 --}}}
 
---{{{ indentation decoder
--- XXX this doesn't handle multi-line strings
--- XXX or VALOF processes
--- XXX or tabs
-
-countIndent :: String -> Int
-countIndent (' ':' ':cs) = 1 + (countIndent cs)
-countIndent (' ':cs) = error "Bad indentation"
-countIndent _ = 0
-
-stripIndent :: String -> String
-stripIndent (' ':cs) = stripIndent cs
-stripIndent cs = cs
-
-stripComment :: String -> String
-stripComment [] = []
-stripComment ('-':'-':s) = []
-stripComment ('"':s) = '"' : stripCommentInString s
-stripComment (c:s) = c : stripComment s
-
-stripCommentInString :: String -> String
-stripCommentInString [] = error "In string at end of line"
-stripCommentInString ('"':s) = '"' : stripComment s
-stripCommentInString (c:s) = c : stripCommentInString s
-
-flatten :: [String] -> String
-flatten ls = concat $ intersperse "\n" $ lines
-  where
-    (initSuffix, lines) = flatten' ls 0
-    rep n i = concat $ take n (repeat i)
-    flatten' [] level = ("", [rep level " __outdent"])
-    flatten' (s:ss) level
-      | stripped == ""   = let (suffix, rest) = flatten' ss level in ("", suffix : rest)
-      | newLevel > level = (rep (newLevel - level) " __indent", stripped : rest)
-      | newLevel < level = (rep (level - newLevel) " __outdent", stripped : rest)
-      | otherwise        = ("", stripped : rest)
-      where newLevel = countIndent s
-            stripped' = stripComment s
-            stripped = (if stripIndent stripped' == "" then "" else (stripped' ++ " __eol")) ++ suffix
-            (suffix, rest) = flatten' ss newLevel
---}}}
-
 --{{{ preprocessor
 -- XXX Doesn't handle preprocessor instructions.
 
 preprocess :: String -> String
-preprocess d = flatten $ lines (d ++ "\n" ++ mainMarker)
+preprocess d = parseIndentation $ lines (d ++ "\n" ++ mainMarker)
 
 readSource :: String -> IO String
 readSource fn = do