diff options
Diffstat (limited to 'cratera/parser.lua')
| -rw-r--r-- | cratera/parser.lua | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/cratera/parser.lua b/cratera/parser.lua deleted file mode 100644 index ade568c..0000000 --- a/cratera/parser.lua +++ /dev/null @@ -1,202 +0,0 @@ ---[[ - This file is part of Cratera Compiler - Copyright (C) 2019 Soni L. - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU Affero General Public License as published by - the Free Software Foundation, either version 3 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 Affero General Public License for more details. - - You should have received a copy of the GNU Affero General Public License - along with this program. If not, see <https://www.gnu.org/licenses/>. ---]] - -local function ts(self) return getmetatable(self).__name end - --- key for STATE -local STATE = setmetatable({}, {__name="STATE", __tostring=ts}) --- key for DATA -local DATA = setmetatable({}, {__name="DATA", __tostring=ts}) --- key for GENERATOR -local GEN = setmetatable({}, {__name="GEN", __tostring=ts}) --- key for DATA OFFSET -local OFFDATA = setmetatable({}, {__name="OFFDATA", __tostring=ts}) --- key for End of Stream -local EOZ = setmetatable({}, {__name="EOZ", __tostring=ts}) --- key for number rules (prevent conflict with hooks) -local NUMBER = setmetatable({}, {__name="NUMBER", __tostring=ts}) --- key for fallback rules (prevent conflict with empty string) -local FALLBACK = setmetatable({}, {__name="FALLBACK", __tostring=ts}) - -local optimize_lookups = {} -for i=0, 255 do - optimize_lookups[i] = string.char(i) -end - -local type, tostring, string_byte - = type, tostring, string.byte - -local function get_next_common(state, in_pos, token) - -- note: must preserve "token" - do not call recursively with a different token - local transition, retry - local st = state[STATE] - if st then - local rule = st[token] - if not rule and token == EOZ then - return in_pos, state - end - if type(token) == "number" then - rule = st[NUMBER] - end - do -- pre-hooks - local pos = -1 - local hook = st[pos] - while hook ~= nil do - if hook then - hook(state, token, rule) - end - pos = pos - 1 - hook = st[pos] - end - end - transition = rule - if transition == nil then - transition = st[FALLBACK] - end - local recheck = true - while recheck do - recheck = false - local tytrans = type(transition) - if tytrans == "string" then - transition = st[transition] - recheck = true - elseif tytrans == "function" then - transition, retry = transition(state, token) - recheck = true - elseif tytrans == "table" and st[transition] ~= nil then - transition = st[transition] - recheck = true - end - end - do -- post-hooks CANNOT USE ipairs HERE BECAUSE Lua 5.1/5.2 - local pos = 1 - local hook = st[pos] - while hook ~= nil do - if hook then - hook(state, token, rule) - end - pos = pos + 1 - hook = st[pos] - end - end - state[STATE] = transition -- may be nil or false - end - -- must NOT use elseif here - the above may set state to nil or false! - if not state[STATE] then - -- unexpected token. stream consumer may attempt to recover, - -- but we do this mostly to differentiate it from "end of stream" condition. - return in_pos - 1, nil, "unexpected token", token, state, st - end - if retry then in_pos = in_pos - 1 end - return in_pos, state, transition -- TODO is this what we should be returning? -end - -local function get_next_table(state, in_pos) - if state[DATA] == nil or #state[DATA] == 0 then - if state[STATE] == nil then - return in_pos, state - else - return get_next_common(state, in_pos, EOZ) - end - end - in_pos = in_pos + 1 - local token = state[DATA][in_pos - state[OFFDATA]] - if token == nil then - state[OFFDATA] = in_pos - 1 - state[DATA] = state[GEN]() - return get_next_table(state, state[OFFDATA]) - end - return get_next_common(state, in_pos, token) -end - -local function get_next_string(state, in_pos) - if state[DATA] == nil or #state[DATA] == 0 then - if state[STATE] == nil then - return in_pos, state - else - return get_next_common(state, in_pos, EOZ) - end - end - in_pos = in_pos + 1 - local token = optimize_lookups[string_byte(state[DATA], in_pos - state[OFFDATA], in_pos - state[OFFDATA])] - if token == nil then - state[OFFDATA] = in_pos - 1 - state[DATA] = state[GEN]() - return get_next_string(state, state[OFFDATA]) - end - return get_next_common(state, in_pos, token) -end - -local function stream(defs, data, state) - local state = state or {} - local fn - state[STATE] = defs - if type(data) == "function" then - state[DATA] = data() - state[GEN] = data - else - state[DATA] = data - state[GEN] = function() end - end - fn = type(state[DATA]) == "table" and get_next_table or get_next_string - state[OFFDATA] = 0 - return fn, state, state[OFFDATA] -end - -local function parse(defs, data, state) - for pos, state, transemsg, etoken, estate in stream(defs, data, state) do - if not state then - -- parse error - return nil, transemsg, etoken, estate - elseif not transemsg then - -- parse success (maybe) - caller needs to check state[STATE] against what it considers a successful state - return state - end - end -end - --- not used by any of the above but useful for others - -local COLLECT = {} - -return { - STATE = STATE, - DATA = DATA, - COLLECT = COLLECT, - EOZ = EOZ, - FALLBACK = FALLBACK, - NUMBER = NUMBER, - stream = stream, - parse = parse, - -- common utility function - selfify = function(t, id) - t[id or "self"] = t - return t - end, - -- common hook - collect_fallback = function(state, token, rule) - if not rule then - local t = state[COLLECT] - t[#t+1] = token - if t.coalesce and #t >= t.coalesce then - t[1] = table.concat(t) - for i=2, #t do t[i] = nil end - end - end - end, -} |