1 -- filename : type-lam.lua
2 -- comment : Pretty printing of (extended) lambda calculus
3 -- author : Matthijs Kooijman, Universiteit Twente, NL
4 -- copyright: Matthijs Kooijman
7 local utf = unicode.utf8
9 if not buffers then buffers = { } end
10 if not buffers.visualizers then buffers.visualizers = { } end
11 if not buffers.visualizers.lam then buffers.visualizers.lam = { } end
13 buffers.visualizers.lam.colors = {
20 buffers.visualizers.lam.symbols = {
21 [' '] = {repr = '\\obs '},
22 ['_'] = {repr = '\\_'},
23 ['->'] = {repr = '\\rightarrow'},
24 -- The default * sits very high above the baseline, \ast (u+2217) looks
26 ['*'] = {repr = '\\ast'},
29 buffers.visualizers.lam.keywords = {
37 function buffers.visualizers.lam.take_symbol(str)
38 -- See if str starts with a symbol, and return the remaining
39 -- string and that symbol. If no symbol from the table is matched,
40 -- just returns the first character.
41 -- We can do a lookup directly, since symbols can be different in
42 -- length, so we just loop over all symbols, trying them in turn.
43 for symbol,props in pairs(buffers.visualizers.lam.symbols) do
44 -- Try to remove symbol from the start of str
45 symbol, newstr = utf.match(str, "^(" .. symbol .. ")(.*)")
47 -- Return this tokens repr, or just the token if it has no
49 res = props.repr or symbol
50 -- Enclose the token in {\style .. }
52 res = "{\\" .. props.style .. " " .. res .. "}"
57 -- No symbol found, just return the first character
58 return utf.match(str, "^(.)(.*)")
61 -- Take a single word from str, if posible. Returns the rest of the string and
63 function buffers.visualizers.lam.take_word(str)
64 res, newstr = utf.match(str, "^(%a+)(.*)")
65 return res, newstr or str
68 function buffers.visualizers.lam.flush_line(str,nested)
69 local result, state = { }, 0
70 local finish, change = buffers.finish_state, buffers.change_state
71 local take_symbol = buffers.visualizers.lam.take_symbol
72 local take_word = buffers.visualizers.lam.take_word
73 -- Set the colorscheme, which is used by finish_state and change_state
74 buffers.currentcolors = buffers.visualizers.lam.colors
79 -- See if the next token is a word
80 res, str = take_word(str)
82 if buffers.visualizers.lam.keywords[res] then
83 -- Make all keywors bold
84 res = "{\\bold " .. res .. "}"
86 -- All other words are unmodified
88 -- The next token is not a word, it must be a symbol
89 res, str = take_symbol(str)
92 -- Append the resulting token
93 result[#result+1] = res
96 state = finish(state, result)
97 buffers.flush_result(result,nested)
100 -- vim: set sw=4 sts=4 expandtab ai: