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authorfiddlosopher <fiddlosopher@788f1e2b-df1e-0410-8736-df70ead52e1b>2009-12-31 01:08:38 +0000
committerfiddlosopher <fiddlosopher@788f1e2b-df1e-0410-8736-df70ead52e1b>2009-12-31 01:08:38 +0000
commita42bae619a222de6b138b590c4d010ab15532d26 (patch)
treee9f3729effbf81447d49192a3ebdada39a4ba9e5
parentd86c01795f24e014ceff9420044b15600cb1f01a (diff)
downloadpandoc-a42bae619a222de6b138b590c4d010ab15532d26.tar.gz
Added templates module.
git-svn-id: https://pandoc.googlecode.com/svn/trunk@1673 788f1e2b-df1e-0410-8736-df70ead52e1b
-rw-r--r--pandoc.cabal1
-rw-r--r--src/Text/Pandoc/Templates.hs111
2 files changed, 112 insertions, 0 deletions
diff --git a/pandoc.cabal b/pandoc.cabal
index cd5e6bbe0..95875b19a 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -193,6 +193,7 @@ Library
Text.Pandoc.Writers.S5
Other-Modules: Text.Pandoc.XML,
Text.Pandoc.TH,
+ Text.Pandoc.Templates
Paths_pandoc
Extensions: CPP, TemplateHaskell, FlexibleInstances
Ghc-Options: -O2 -Wall
diff --git a/src/Text/Pandoc/Templates.hs b/src/Text/Pandoc/Templates.hs
new file mode 100644
index 000000000..7cfb697cf
--- /dev/null
+++ b/src/Text/Pandoc/Templates.hs
@@ -0,0 +1,111 @@
+{-
+Copyright (C) 2009 John MacFarlane <jgm@berkeley.edu>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+-}
+
+{- |
+ Module : Text.Pandoc.Templates
+ Copyright : Copyright (C) 2009 John MacFarlane
+ License : GNU GPL, version 2 or above
+
+ Maintainer : John MacFarlane <jgm@berkeley.edu>
+ Stability : alpha
+ Portability : portable
+
+A simple templating system with variable substitution and conditionals.
+Example:
+
+> > renderTemplate [("name","Sam"),("salary","50,000")] $
+> "Hi, $name$. $if(salary)$You make $$$salary$.$else$No salary data.$endif$"
+> > "Hi, John. You make $50,000."
+
+A slot for an interpolated variable is a variable name surrounded
+by dollar signs. To include a literal @$@ in your template, use
+@$$@. Variable names must begin with a letter and can contain letters,
+numbers, @_@, and @-@.
+
+A conditional begins with @$if(variable_name)$@ and ends with @$endif$@.
+It may optionally contain an @$else$@ section. The if section is
+used if @variable_name@ has a non-null value, otherwise the else section
+is used.
+-}
+
+module Text.Pandoc.Templates (renderTemplate) where
+
+import Text.ParserCombinators.Parsec
+import Control.Monad (liftM)
+
+-- | Renders a template
+renderTemplate :: [(String,String)] -- ^ Assoc. list of values for variables
+ -> String -- ^ Template
+ -> String
+renderTemplate vals templ =
+ case runParser (do x <- parseTemplate; eof; return x) vals "template" templ of
+ Left e -> show e
+ Right r -> concat r
+
+reservedWords :: [String]
+reservedWords = ["else","endif"]
+
+parseTemplate :: GenParser Char [(String,String)] [String]
+parseTemplate =
+ many $ plaintext <|> escapedDollar <|> conditional <|> variable
+
+plaintext :: GenParser Char [(String,String)] String
+plaintext = many1 $ satisfy (/='$')
+
+escapedDollar :: GenParser Char [(String,String)] String
+escapedDollar = try $ string "$$" >> return "$"
+
+conditional :: GenParser Char [(String,String)] String
+conditional = try $ do
+ string "$if("
+ id' <- ident
+ string ")$"
+ skipMany (oneOf " \t")
+ optional newline
+ ifContents <- liftM concat parseTemplate
+ elseContents <- option "" $ do try (string "$else$")
+ skipMany (oneOf " \t")
+ optional newline
+ liftM concat parseTemplate
+ string "$endif$"
+ skipMany (oneOf " \t")
+ optional newline
+ st <- getState
+ return $ case lookup id' st of
+ Just "" -> elseContents
+ Just _ -> ifContents
+ Nothing -> elseContents
+
+ident :: GenParser Char [(String,String)] String
+ident = do
+ first <- letter
+ rest <- many (alphaNum <|> oneOf "_-")
+ let id' = first : rest
+ if id' `elem` reservedWords
+ then pzero
+ else return id'
+
+variable :: GenParser Char [(String,String)] String
+variable = try $ do
+ char '$'
+ id' <- ident
+ char '$'
+ st <- getState
+ return $ case lookup id' st of
+ Just val -> val
+ Nothing -> ""