Adding more robust variable syntax

bytbox · Apr 22, 2012 · 2907197 · 2907197
1 parent 4e4a69f
commit 2907197
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Showing 3 changed files with 8 additions and 4 deletions.
diff --git a/Makefile b/Makefile
@@ -1,6 +1,6 @@
 all: main
 
-main: main.hs
+main: main.hs Text/Format.lhs
 	ghc --make $@
 
 clean:

diff --git a/Text/Format.lhs b/Text/Format.lhs
@@ -12,10 +12,14 @@
 
 > ident :: Parsec String () FormatPart
 > ident = do
->           char '$'
 >           x <- many1 (alphaNum <|> char '_')
 >           return $ Var x
 
+> variable =
+>   try (char '$' >> ident)
+>   <|>
+>   try (char '$' >> between (char '{') (char '}') ident)
+
 > special = do
 >             char '$' >> char '$'
 >             return $ Raw '$'
@@ -25,7 +29,7 @@
 
 > formatParser :: Parsec String () Format
 > formatParser = do
->   xs <- many (try raw <|> try special <|> ident)
+>   xs <- many (try raw <|> try special <|> variable)
 >   eof
 >   return xs
 

diff --git a/main.hs b/main.hs
@@ -6,7 +6,7 @@ import Data.Maybe (fromJust)
 
 import Text.Format
 
-formatString = "$p1 - $p2 [$$$cost]"
+formatString = "$p1 - ${p2} [$$$cost]"
 
 data Record = Record
   { p1    :: Int