1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
{-
Copyright © 2012-2017 John MacFarlane <jgm@berkeley.edu>
2017 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
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
-}
{-# LANGUAGE FlexibleInstances #-}
{- |
Module : Text.Pandoc.Lua.Util
Copyright : © 2012–2016 John MacFarlane,
© 2017 Albert Krewinkel
License : GNU GPL, version 2 or above
Maintainer : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
Stability : alpha
Lua utility functions.
-}
module Text.Pandoc.Lua.Util
( adjustIndexBy
, getTable
, setTable
, addValue
, getRawInt
, setRawInt
, addRawInt
, keyValuePairs
, PushViaCall
, pushViaCall
, pushViaConstructor
) where
import Scripting.Lua
( LuaState, StackValue(..)
, call, getglobal2, gettable, next, pop, pushnil, rawgeti, rawseti, settable
)
-- | Adjust the stack index, assuming that @n@ new elements have been pushed on
-- the stack.
adjustIndexBy :: Int -> Int -> Int
adjustIndexBy idx n =
if idx < 0
then idx - n
else idx
-- | Get value behind key from table at given index.
getTable :: (StackValue a, StackValue b) => LuaState -> Int -> a -> IO (Maybe b)
getTable lua idx key = do
push lua key
gettable lua (idx `adjustIndexBy` 1)
peek lua (-1) <* pop lua 1
-- | Set value for key for table at the given index
setTable :: (StackValue a, StackValue b) => LuaState -> Int -> a -> b -> IO ()
setTable lua idx key value = do
push lua key
push lua value
settable lua (idx `adjustIndexBy` 2)
-- | Add a key-value pair to the table at the top of the stack
addValue :: (StackValue a, StackValue b) => LuaState -> a -> b -> IO ()
addValue lua = setTable lua (-1)
-- | Get value behind key from table at given index.
getRawInt :: StackValue a => LuaState -> Int -> Int -> IO (Maybe a)
getRawInt lua idx key =
rawgeti lua idx key
*> peek lua (-1)
<* pop lua 1
-- | Set numeric key/value in table at the given index
setRawInt :: StackValue a => LuaState -> Int -> Int -> a -> IO ()
setRawInt lua idx key value = do
push lua value
rawseti lua (idx `adjustIndexBy` 1) key
-- | Set numeric key/value in table at the top of the stack.
addRawInt :: StackValue a => LuaState -> Int -> a -> IO ()
addRawInt lua = setRawInt lua (-1)
-- | Try reading the table under the given index as a list of key-value pairs.
keyValuePairs :: (StackValue a, StackValue b)
=> LuaState -> Int -> IO (Maybe [(a, b)])
keyValuePairs lua idx = do
pushnil lua
sequence <$> remainingPairs
where
remainingPairs = do
res <- nextPair
case res of
Nothing -> return []
Just a -> (a:) <$> remainingPairs
nextPair :: (StackValue a, StackValue b) => IO (Maybe (Maybe (a,b)))
nextPair = do
hasNext <- next lua (idx `adjustIndexBy` 1)
if hasNext
then do
val <- peek lua (-1)
key <- peek lua (-2)
pop lua 1 -- removes the value, keeps the key
return $ Just <$> ((,) <$> key <*> val)
else do
return Nothing
-- | Helper class for pushing a single value to the stack via a lua function.
-- See @pushViaCall@.
class PushViaCall a where
pushViaCall' :: LuaState -> String -> IO () -> Int -> a
instance PushViaCall (IO ()) where
pushViaCall' lua fn pushArgs num = do
getglobal2 lua fn
pushArgs
call lua num 1
instance (StackValue a, PushViaCall b) => PushViaCall (a -> b) where
pushViaCall' lua fn pushArgs num x =
pushViaCall' lua fn (pushArgs *> push lua x) (num + 1)
-- | Push an value to the stack via a lua function. The lua function is called
-- with all arguments that are passed to this function and is expected to return
-- a single value.
pushViaCall :: PushViaCall a => LuaState -> String -> a
pushViaCall lua fn = pushViaCall' lua fn (return ()) 0
-- | Call a pandoc element constructor within lua, passing all given arguments.
pushViaConstructor :: PushViaCall a => LuaState -> String -> a
pushViaConstructor lua pandocFn = pushViaCall lua ("pandoc." ++ pandocFn)
|
