"prettyfour"
}
-buffers.visualizers.lam.tokens = {
+-- Symbols that should have a different representation
+buffers.visualizers.lam.symbols = {
[' '] = {repr = '\\obs '},
['_'] = {repr = '\\_'},
['->'] = {repr = '\\rightarrow'},
-- The default * sits very high above the baseline, \ast (u+2217) looks
-- better.
['*'] = {repr = '\\ast'},
- ['case'] = {style = 'bold'},
- ['of'] = {style = 'bold'},
- ['let'] = {style = 'bold'},
- ['in'] = {style = 'bold'},
+ ['~'] = {repr = '\\sim'},
}
+
+-- Keywords that should be bold
+buffers.visualizers.lam.keywords = {
+ ['case'] = {},
+ ['of'] = {},
+ ['let'] = {},
+ ['in'] = {},
+}
+
+-- See if str starts with a symbol, and return the remaining string and that
+-- symbol. If no symbol from the table is matched, just returns the first
+-- character. We can do a lookup directly, since symbols can be different in
+-- length, so we just loop over all symbols, trying them in turn.
+function buffers.visualizers.lam.take_symbol(str)
+ for symbol,props in pairs(buffers.visualizers.lam.symbols) do
+ -- Try to remove symbol from the start of str
+ symbol, newstr = utf.match(str, "^(" .. symbol .. ")(.*)")
+ if symbol then
+ -- Return this tokens repr, or just the token if it has no
+ -- repr.
+ res = props.repr or symbol
+ -- Enclose the token in {\style .. }
+ if props.style then
+ res = "{\\" .. props.style .. " " .. res .. "}"
+ end
+ return res, newstr
+ end
+ end
+ -- No symbol found, just return the first character
+ return utf.match(str, "^(.)(.*)")
+end
+
+-- Take a single word from str, if posible. Returns the rest of the string and
+-- the word taken.
+function buffers.visualizers.lam.take_word(str)
+ -- A word must always start with a-z (in particular, λ is not a valid
+ -- start of a word).
+ res, newstr = utf.match(str, "^([a-zA-Z][%a%d_]+)(.*)")
+ return res, newstr or str
+end
+
+-- Tries to match each of the patterns and returns the captures of the first
+-- matching pattern (up to 5 captures are supported). Returns nil when nothing
+-- matches.
+function buffers.visualizers.lam.match_mul(str, patterns)
+ for i, pat in ipairs(patterns) do
+ a, b, c, d, e = utf.match(str, pat)
+ if a then
+ return a, b, c, d, e
+ end
+ end
+ return nil
+end
+
+-- Find any subscripts in the given word and typeset them
+function buffers.visualizers.lam.do_subscripts(word)
+ local match_mul = buffers.visualizers.lam.match_mul
+ base, sub = match_mul(res, submatches)
+ if sub then
+ word = base .. "\\low{" .. sub .. "}"
+ -- After a word has been used as a base, allow subscripts
+ -- without _, even for non-numbers.
+ if not bases[base] then
+ -- Register that we've added this base
+ bases[base] = true
+ -- Add a pattern for this base
+ submatches[#submatches+1] = "^(" .. base .. ")([%a%d,]+)$"
+ end
+ end
+ return word
+end
+
+function buffers.visualizers.lam.begin_of_buffer(type, name)
+ -- Initially allow subscripts using _ or just appending a number (later,
+ -- we will add extra patterns here.
+ submatches = {"^(.*)_([%a%d,]+)$", "^(.*[^%d])(%d+)$"}
+ -- This stores all the bases we've encountered so far (to prevent
+ -- duplicates). For each of them there will be a pattern in submatches
+ -- above.
+ bases = {}
+end
+
function buffers.visualizers.lam.flush_line(str,nested)
local result, state = { }, 0
local finish, change = buffers.finish_state, buffers.change_state
+ local take_symbol = buffers.visualizers.lam.take_symbol
+ local take_word = buffers.visualizers.lam.take_word
+ local do_subscripts = buffers.visualizers.lam.do_subscripts
-- Set the colorscheme, which is used by finish_state and change_state
buffers.currentcolors = buffers.visualizers.lam.colors
-
while str ~= "" do
- found = false
- for tok,props in pairs(buffers.visualizers.lam.tokens) do
- -- Try to remove tok from the start of str
- str, count = utf.gsub(str, "^" .. tok, "")
- if count ~= 0 then
- -- Replace the token with the repr, or just itself
- result[#result+1] = props.repr or tok
- -- Enclose the token in {\style .. }
- if props.style then
- result[#result] = "{\\" .. props.style ..
- " " .. result[#result] ..
- "}"
- end
- -- We found a token, now start over
- found = true
- break
+ local found = false
+ local word, symbol
+ -- See if the next token is a word
+ word, str = take_word(str)
+ if word then
+ if buffers.visualizers.lam.keywords[res] then
+ -- Make all keywords bold
+ word = "{\\bold " .. word .. "}"
+ else
+ -- Process any subscripts in the word
+ word = do_subscripts(word)
end
+ else
+ -- The next token is not a word, it must be a symbol
+ symbol, str = take_symbol(str)
end
- if not found then
- -- Take a full word, or a single character. Taking a full word is
- -- to prevent matching "in" in "bind" , for example.
- result[#result+1] = utf.match(str, "^%a+") or utf.sub(str, 1, 1)
- str = utf.sub(str, utf.len(result[#result]) + 1)
- end
+
+ -- Append the resulting token
+ result[#result+1] = word or symbol
end
+
state = finish(state, result)
buffers.flush_result(result,nested)
end
projects / matthijs / master-project / report.git / blobdiff