lite-xl/data/core/tokenizer.lua

364 lines
13 KiB
Lua

local core = require "core"
local syntax = require "core.syntax"
local tokenizer = {}
local bad_patterns = {}
local function push_token(t, type, text)
if not text or #text == 0 then return end
type = type or "normal"
local prev_type = t[#t-1]
local prev_text = t[#t]
if prev_type and (prev_type == type or prev_text:ufind("^%s*$")) then
t[#t-1] = type
t[#t] = prev_text .. text
else
table.insert(t, type)
table.insert(t, text)
end
end
local function push_tokens(t, syn, pattern, full_text, find_results)
if #find_results > 2 then
-- We do some manipulation with find_results so that it's arranged
-- like this:
-- { start, end, i_1, i_2, i_3, …, i_last }
-- Each position spans characters from i_n to ((i_n+1) - 1), to form
-- consecutive spans of text.
--
-- Insert the start index at i_1 to make iterating easier
table.insert(find_results, 3, find_results[1])
-- Copy the ending index to the end of the table, so that an ending index
-- always follows a starting index after position 3 in the table.
table.insert(find_results, find_results[2] + 1)
-- Then, we just iterate over our modified table.
for i = 3, #find_results - 1 do
local start = find_results[i]
local fin = find_results[i + 1] - 1
local type = pattern.type[i - 2]
-- ↑ (i - 2) to convert from [3; n] to [1; n]
if fin >= start then
local text = full_text:usub(start, fin)
push_token(t, syn.symbols[text] or type, text)
end
end
else
local start, fin = find_results[1], find_results[2]
local text = full_text:usub(start, fin)
push_token(t, syn.symbols[text] or pattern.type, text)
end
end
-- State is a string of bytes, where the count of bytes represents the depth
-- of the subsyntax we are currently in. Each individual byte represents the
-- index of the pattern for the current subsyntax in relation to its parent
-- syntax. Using a string of bytes allows us to have as many subsyntaxes as
-- bytes can be stored on a string while keeping some level of performance in
-- comparison to a Lua table. The only limitation is that a syntax would not
-- be able to contain more than 255 patterns.
--
-- Lets say a state contains 2 bytes byte #1 with value `3` and byte #2 with
-- a value of `5`. This would mean that on the parent syntax at index `3` a
-- pattern subsyntax that matched current text was found, then inside that
-- subsyntax another subsyntax pattern at index `5` that matched current text
-- was also found.
-- Calling `push_subsyntax` appends the current subsyntax pattern index to the
-- state and increases the stack depth. Calling `pop_subsyntax` clears the
-- last appended subsyntax and decreases the stack.
local function retrieve_syntax_state(incoming_syntax, state)
local current_syntax, subsyntax_info, current_pattern_idx, current_level =
incoming_syntax, nil, state:byte(1) or 0, 1
if
current_pattern_idx > 0
and
current_syntax.patterns[current_pattern_idx]
then
-- If the state is not empty we iterate over each byte, and find which
-- syntax we're using. Rather than walking the bytes, and calling into
-- `syntax` each time, we could probably cache this in a single table.
for i = 1, #state do
local target = state:byte(i)
if target ~= 0 then
if current_syntax.patterns[target].syntax then
subsyntax_info = current_syntax.patterns[target]
current_syntax = type(subsyntax_info.syntax) == "table" and
subsyntax_info.syntax or syntax.get(subsyntax_info.syntax)
current_pattern_idx = 0
current_level = i+1
else
current_pattern_idx = target
break
end
else
break
end
end
end
return current_syntax, subsyntax_info, current_pattern_idx, current_level
end
---Return the list of syntaxes used in the specified state.
---@param base_syntax table @The initial base syntax (the syntax of the file)
---@param state string @The state of the tokenizer to extract from
---@return table @Array of syntaxes starting from the innermost one
function tokenizer.extract_subsyntaxes(base_syntax, state)
local current_syntax
local t = {}
repeat
current_syntax = retrieve_syntax_state(base_syntax, state)
table.insert(t, current_syntax)
state = string.sub(state, 2)
until #state == 0
return t
end
local function report_bad_pattern(log_fn, syntax, pattern_idx, msg, ...)
if not bad_patterns[syntax] then
bad_patterns[syntax] = { }
end
if bad_patterns[syntax][pattern_idx] then return end
bad_patterns[syntax][pattern_idx] = true
log_fn("Malformed pattern #%d in %s language plugin. " .. msg,
pattern_idx, syntax.name or "unnamed", ...)
end
---@param incoming_syntax table
---@param text string
---@param state string
function tokenizer.tokenize(incoming_syntax, text, state)
local res = {}
local i = 1
if #incoming_syntax.patterns == 0 then
return { "normal", text }
end
state = state or string.char(0)
-- incoming_syntax : the parent syntax of the file.
-- state : a string of bytes representing syntax state (see above)
-- current_syntax : the syntax we're currently in.
-- subsyntax_info : info about the delimiters of this subsyntax.
-- current_pattern_idx: the index of the pattern we're on for this syntax.
-- current_level : how many subsyntaxes deep we are.
local current_syntax, subsyntax_info, current_pattern_idx, current_level =
retrieve_syntax_state(incoming_syntax, state)
-- Should be used to set the state variable. Don't modify it directly.
local function set_subsyntax_pattern_idx(pattern_idx)
current_pattern_idx = pattern_idx
local state_len = #state
if current_level > state_len then
state = state .. string.char(pattern_idx)
elseif state_len == 1 then
state = string.char(pattern_idx)
else
state = ("%s%s%s"):format(
state:sub(1,current_level-1),
string.char(pattern_idx),
state:sub(current_level+1)
)
end
end
local function push_subsyntax(entering_syntax, pattern_idx)
set_subsyntax_pattern_idx(pattern_idx)
current_level = current_level + 1
subsyntax_info = entering_syntax
current_syntax = type(entering_syntax.syntax) == "table" and
entering_syntax.syntax or syntax.get(entering_syntax.syntax)
current_pattern_idx = 0
end
local function pop_subsyntax()
current_level = current_level - 1
state = string.sub(state, 1, current_level)
set_subsyntax_pattern_idx(0)
current_syntax, subsyntax_info, current_pattern_idx, current_level =
retrieve_syntax_state(incoming_syntax, state)
end
local function find_text(text, p, offset, at_start, close)
local target, res = p.pattern or p.regex, { 1, offset - 1 }
local p_idx = close and 2 or 1
local code = type(target) == "table" and target[p_idx] or target
if p.whole_line == nil then p.whole_line = { } end
if p.whole_line[p_idx] == nil then
-- Match patterns that start with '^'
p.whole_line[p_idx] = code:umatch("^%^") and true or false
if p.whole_line[p_idx] then
-- Remove '^' from the beginning of the pattern
if type(target) == "table" then
target[p_idx] = code:usub(2)
else
p.pattern = p.pattern and code:usub(2)
p.regex = p.regex and code:usub(2)
end
end
end
if p.regex and type(p.regex) ~= "table" then
p._regex = p._regex or regex.compile(p.regex)
code = p._regex
end
repeat
local next = res[2] + 1
-- If the pattern contained '^', allow matching only the whole line
if p.whole_line[p_idx] and next > 1 then
return
end
res = p.pattern and { text:ufind((at_start or p.whole_line[p_idx]) and "^" .. code or code, next) }
or { regex.find(code, text, text:ucharpos(next), (at_start or p.whole_line[p_idx]) and regex.ANCHORED or 0) }
if p.regex and #res > 0 then -- set correct utf8 len for regex result
local char_pos_1 = res[1] > next and string.ulen(text:sub(1, res[1])) or next
local char_pos_2 = string.ulen(text:sub(1, res[2]))
for i=3,#res do
res[i] = string.ulen(text:sub(1, res[i] - 1)) + 1
end
res[1] = char_pos_1
res[2] = char_pos_2
end
if not res[1] then return end
if res[1] and target[3] then
-- Check to see if the escaped character is there,
-- and if it is not itself escaped.
local count = 0
for i = res[1] - 1, 1, -1 do
if text:ubyte(i) ~= target[3]:ubyte() then break end
count = count + 1
end
if count % 2 == 0 then
-- The match is not escaped, so confirm it
break
else
-- The match is escaped, so avoid it
res[1] = false
end
end
until at_start or not close or not target[3]
return table.unpack(res)
end
local text_len = text:ulen()
while i <= text_len do
-- continue trying to match the end pattern of a pair if we have a state set
if current_pattern_idx > 0 then
local p = current_syntax.patterns[current_pattern_idx]
local s, e = find_text(text, p, i, false, true)
-- Use the first token type specified in the type table for the "middle"
-- part of the subsyntax.
local token_type = type(p.type) == "table" and p.type[1] or p.type
local cont = true
-- If we're in subsyntax mode, always check to see if we end our syntax
-- first, before the found delimeter, as ending the subsyntax takes
-- precedence over ending the delimiter in the subsyntax.
if subsyntax_info then
local ss, se = find_text(text, subsyntax_info, i, false, true)
-- If we find that we end the subsyntax before the
-- delimiter, push the token, and signal we shouldn't
-- treat the bit after as a token to be normally parsed
-- (as it's the syntax delimiter).
if ss and (s == nil or ss < s) then
push_token(res, token_type, text:usub(i, ss - 1))
i = ss
cont = false
end
end
-- If we don't have any concerns about syntax delimiters,
-- continue on as normal.
if cont then
if s then
push_token(res, token_type, text:usub(i, e))
set_subsyntax_pattern_idx(0)
i = e + 1
else
push_token(res, token_type, text:usub(i))
break
end
end
end
-- General end of syntax check. Applies in the case where
-- we're ending early in the middle of a delimiter, or
-- just normally, upon finding a token.
while subsyntax_info do
local find_results = { find_text(text, subsyntax_info, i, true, true) }
local s, e = find_results[1], find_results[2]
if s then
push_tokens(res, current_syntax, subsyntax_info, text, find_results)
-- On finding unescaped delimiter, pop it.
pop_subsyntax()
i = e + 1
else
break
end
end
-- find matching pattern
local matched = false
for n, p in ipairs(current_syntax.patterns) do
local find_results = { find_text(text, p, i, true, false) }
if find_results[1] then
local type_is_table = type(p.type) == "table"
local n_types = type_is_table and #p.type or 1
if #find_results == 2 and type_is_table then
report_bad_pattern(core.warn, current_syntax, n,
"Token type is a table, but a string was expected.")
p.type = p.type[1]
elseif #find_results - 1 > n_types then
report_bad_pattern(core.error, current_syntax, n,
"Not enough token types: got %d needed %d.", n_types, #find_results - 1)
elseif #find_results - 1 < n_types then
report_bad_pattern(core.warn, current_syntax, n,
"Too many token types: got %d needed %d.", n_types, #find_results - 1)
end
-- matched pattern; make and add tokens
push_tokens(res, current_syntax, p, text, find_results)
-- update state if this was a start|end pattern pair
if type(p.pattern or p.regex) == "table" then
-- If we have a subsyntax, push that onto the subsyntax stack.
if p.syntax then
push_subsyntax(p, n)
else
set_subsyntax_pattern_idx(n)
end
end
-- move cursor past this token
i = find_results[2] + 1
matched = true
break
end
end
-- consume character if we didn't match
if not matched then
push_token(res, "normal", text:usub(i, i))
i = i + 1
end
end
return res, state
end
local function iter(t, i)
i = i + 2
local type, text = t[i], t[i+1]
if type then
return i, type, text
end
end
function tokenizer.each_token(t)
return iter, t, -1
end
return tokenizer