From 81eadfd99ad3e905b806cc6c80ab0fea0185286f Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Wed, 26 May 2021 22:50:35 -0700
Subject: [PATCH] LaTeX reader: improve `\def` and implement `\newif`.
- Improve parsing of `\def` macros. We previously set "verbatim mode"
even for parsing the initial `\def`; this caused problems for things
like
```
\def\foo{\def\bar{BAR}}
\foo
\bar
```
- Implement `\newif`.
- Add tests.
---
src/Text/Pandoc/Readers/LaTeX/Macro.hs | 59 ++++++++++++++++++------
src/Text/Pandoc/Readers/LaTeX/Parsing.hs | 19 +++++++-
test/command/newif.md | 55 ++++++++++++++++++++++
3 files changed, 118 insertions(+), 15 deletions(-)
create mode 100644 test/command/newif.md
diff --git a/src/Text/Pandoc/Readers/LaTeX/Macro.hs b/src/Text/Pandoc/Readers/LaTeX/Macro.hs
index 607f5438c..5495a8e74 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Macro.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Macro.hs
@@ -14,6 +14,7 @@ import Text.Pandoc.Parsing hiding (blankline, mathDisplay, mathInline,
import Control.Applicative ((<|>), optional)
import qualified Data.Map as M
import Data.Text (Text)
+import qualified Data.Text as T
macroDef :: (PandocMonad m, Monoid a) => (Text -> a) -> LP m a
macroDef constructor = do
@@ -22,9 +23,11 @@ macroDef constructor = do
guardDisabled Ext_latex_macros)
<|> return mempty
where commandDef = do
- (name, macro') <- newcommand <|> letmacro <|> defmacro
+ nameMacroPairs <- newcommand <|> letmacro <|> defmacro <|> newif
guardDisabled Ext_latex_macros <|>
- updateState (\s -> s{ sMacros = M.insert name macro' (sMacros s) })
+ mapM_ (\(name, macro') ->
+ updateState (\s -> s{ sMacros = M.insert name macro'
+ (sMacros s) })) nameMacroPairs
environmentDef = do
mbenv <- newenvironment
case mbenv of
@@ -40,7 +43,7 @@ macroDef constructor = do
-- @\newcommand{\envname}[n-args][default]{begin}@
-- @\newcommand{\endenvname}@
-letmacro :: PandocMonad m => LP m (Text, Macro)
+letmacro :: PandocMonad m => LP m [(Text, Macro)]
letmacro = do
controlSeq "let"
(name, contents) <- withVerbatimMode $ do
@@ -53,18 +56,47 @@ letmacro = do
contents <- bracedOrToken
return (name, contents)
contents' <- doMacros' 0 contents
- return (name, Macro ExpandWhenDefined [] Nothing contents')
+ return [(name, Macro ExpandWhenDefined [] Nothing contents')]
-defmacro :: PandocMonad m => LP m (Text, Macro)
-defmacro = try $
+defmacro :: PandocMonad m => LP m [(Text, Macro)]
+defmacro = do
-- we use withVerbatimMode, because macros are to be expanded
-- at point of use, not point of definition
+ controlSeq "def"
withVerbatimMode $ do
- controlSeq "def"
Tok _ (CtrlSeq name) _ <- anyControlSeq
argspecs <- many (argspecArg <|> argspecPattern)
contents <- bracedOrToken
- return (name, Macro ExpandWhenUsed argspecs Nothing contents)
+ return [(name, Macro ExpandWhenUsed argspecs Nothing contents)]
+
+-- \newif\iffoo' defines:
+-- \iffoo to be \iffalse
+-- \footrue to be a command that defines \iffoo to be \iftrue
+-- \foofalse to be a command that defines \iffoo to be \iffalse
+newif :: PandocMonad m => LP m [(Text, Macro)]
+newif = do
+ controlSeq "newif"
+ withVerbatimMode $ do
+ Tok pos (CtrlSeq name) _ <- anyControlSeq
+ -- \def\iffoo\iffalse
+ -- \def\footrue{\def\iffoo\iftrue}
+ -- \def\foofalse{\def\iffoo\iffalse}
+ let base = T.drop 2 name
+ return [ (name, Macro ExpandWhenUsed [] Nothing
+ [Tok pos (CtrlSeq "iffalse") "\\iffalse"])
+ , (base <> "true",
+ Macro ExpandWhenUsed [] Nothing
+ [ Tok pos (CtrlSeq "def") "\\def"
+ , Tok pos (CtrlSeq name) ("\\" <> name)
+ , Tok pos (CtrlSeq "iftrue") "\\iftrue"
+ ])
+ , (base <> "false",
+ Macro ExpandWhenUsed [] Nothing
+ [ Tok pos (CtrlSeq "def") "\\def"
+ , Tok pos (CtrlSeq name) ("\\" <> name)
+ , Tok pos (CtrlSeq "iffalse") "\\iffalse"
+ ])
+ ]
argspecArg :: PandocMonad m => LP m ArgSpec
argspecArg = do
@@ -77,10 +109,9 @@ argspecPattern =
(toktype' == Symbol || toktype' == Word) &&
(txt /= "{" && txt /= "\\" && txt /= "}")))
-newcommand :: PandocMonad m => LP m (Text, Macro)
+newcommand :: PandocMonad m => LP m [(Text, Macro)]
newcommand = do
- pos <- getPosition
- Tok _ (CtrlSeq mtype) _ <- controlSeq "newcommand" <|>
+ Tok pos (CtrlSeq mtype) _ <- controlSeq "newcommand" <|>
controlSeq "renewcommand" <|>
controlSeq "providecommand" <|>
controlSeq "DeclareMathOperator" <|>
@@ -112,9 +143,9 @@ newcommand = do
Just macro
| mtype == "newcommand" -> do
report $ MacroAlreadyDefined txt pos
- return (name, macro)
- | mtype == "providecommand" -> return (name, macro)
- _ -> return (name, Macro ExpandWhenUsed argspecs optarg contents)
+ return [(name, macro)]
+ | mtype == "providecommand" -> return [(name, macro)]
+ _ -> return [(name, Macro ExpandWhenUsed argspecs optarg contents)]
newenvironment :: PandocMonad m => LP m (Maybe (Text, Macro, Macro))
newenvironment = do
diff --git a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
index 1c77eb299..a17b1f324 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
@@ -113,7 +113,6 @@ import Text.Pandoc.Readers.LaTeX.Types (ExpansionPoint (..), Macro (..),
ArgSpec (..), Tok (..), TokType (..))
import Text.Pandoc.Shared
import Text.Parsec.Pos
--- import Debug.Trace
newtype DottedNum = DottedNum [Int]
deriving (Show, Eq)
@@ -563,8 +562,26 @@ trySpecialMacro "xspace" ts = do
Tok pos Word t : _
| startsWithAlphaNum t -> return $ Tok pos Spaces " " : ts'
_ -> return ts'
+trySpecialMacro "iftrue" ts = handleIf True ts
+trySpecialMacro "iffalse" ts = handleIf False ts
trySpecialMacro _ _ = mzero
+handleIf :: PandocMonad m => Bool -> [Tok] -> LP m [Tok]
+handleIf b ts = do
+ res' <- lift $ runParserT (ifParser b) defaultLaTeXState "tokens" ts
+ case res' of
+ Left _ -> Prelude.fail "Could not parse conditional"
+ Right ts' -> return ts'
+
+ifParser :: PandocMonad m => Bool -> LP m [Tok]
+ifParser b = do
+ ifToks <- many (notFollowedBy (controlSeq "else" <|> controlSeq "fi")
+ *> anyTok)
+ elseToks <- (controlSeq "else" >> manyTill anyTok (controlSeq "fi"))
+ <|> ([] <$ controlSeq "fi")
+ rest <- getInput
+ return $ (if b then ifToks else elseToks) ++ rest
+
startsWithAlphaNum :: Text -> Bool
startsWithAlphaNum t =
case T.uncons t of
diff --git a/test/command/newif.md b/test/command/newif.md
new file mode 100644
index 000000000..f444f14c9
--- /dev/null
+++ b/test/command/newif.md
@@ -0,0 +1,55 @@
+```
+% pandoc -f latex -t plain
+\iftrue
+should print
+\iftrue
+should print
+\else
+should not print
+\fi
+\else
+should not print
+\fi
+
+\iffalse
+should not print
+\else
+\iftrue
+should print
+\else
+should not print
+\fi
+\fi
+
+\newif\ifepub
+
+\ifepub
+should not print
+\fi
+
+\epubtrue
+
+\ifepub
+should print
+\else
+should not print
+\fi
+
+\epubfalse
+
+\ifepub
+should not print
+\else
+should print
+\fi
+^D
+should print
+
+should print
+
+should print
+
+should print
+
+should print
+```