diff options
| -rw-r--r-- | .editorconfig | 7 | ||||
| -rw-r--r-- | .lua-format | 27 | ||||
| -rw-r--r-- | LICENSE | 674 | ||||
| -rw-r--r-- | Makefile | 7 | ||||
| -rw-r--r-- | README.md | 65 | ||||
| -rw-r--r-- | init.lua | 645 | ||||
| -rw-r--r-- | json.lua | 194 |
7 files changed, 1619 insertions, 0 deletions
diff --git a/.editorconfig b/.editorconfig new file mode 100644 index 0000000..f22620f --- /dev/null +++ b/.editorconfig @@ -0,0 +1,7 @@ +# http://editorconfig.org + +root = true + +[*.lua] +indent_style = space +indent_size = 2 diff --git a/.lua-format b/.lua-format new file mode 100644 index 0000000..43ff46c --- /dev/null +++ b/.lua-format @@ -0,0 +1,27 @@ +column_limit: 100 +indent_width: 2 +use_tab: false +spaces_before_call: 1 +keep_simple_control_block_one_line: false +keep_simple_function_one_line: false +align_args: true +break_after_functioncall_lp: false +break_before_functioncall_rp: false +spaces_inside_functioncall_parens: false +spaces_inside_functiondef_parens: false +align_parameter: true +chop_down_parameter: false +break_after_functiondef_lp: false +break_before_functiondef_rp: false +align_table_field: true +break_after_table_lb: true +break_before_table_rb: true +chop_down_table: true +chop_down_kv_table: true +table_sep: "," +extra_sep_at_table_end: true +column_table_limit: 80 +spaces_inside_table_braces: false +break_after_operator: true +double_quote_to_single_quote: true +spaces_around_equals_in_field: true @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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If not, see <https://www.gnu.org/licenses/>. + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + <program> Copyright (C) <year> <name of author> + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +<https://www.gnu.org/licenses/>. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +<https://www.gnu.org/licenses/why-not-lgpl.html>. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..086ebc3 --- /dev/null +++ b/Makefile @@ -0,0 +1,7 @@ +.PHONY: check format + +check: + luacheck --globals=vis -- init.lua + +format: + lua-format -i init.lua diff --git a/README.md b/README.md new file mode 100644 index 0000000..707fd01 --- /dev/null +++ b/README.md @@ -0,0 +1,65 @@ +# vis-lspc - language server protocol client for the vis editor + +## Whats working + +vis-lspc currently supports: + * `textDocument/completion` + * `textDocument/declaration` + * `textDocument/definition` + * `textDocument/typeDefinition` + * `textDocument/implementation` + +## Whats not working + +Everything else. + +Especially `textDocument/didChange` must be implemented before vis-lspc is somewhat usable. +To my knowledge the is currently no good way to detect file changes vis the Lua API. +But this is essential to support [Text Synchronization](https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textSynchronization) which is required by the +LSP protocol. + +A dirty workaround could be to send the whole file content in a `textDocument/didChange` +method call before calling any other method. +If someone can come up with an idea how to solve this I would appreciate contributions. + +We never send any client capabilities. + +Communicating with language-servers via other channels than stdin/stdout. + +Currently only clangd is available and somewhat tested. + +There should be a mapping between vis syntax/lexer names and LSP [languageId](https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocumentItem). +For example the syntax for C code in vis is called 'ansi_c' and in LSP 'c'. + +## Usage + +Note that till `textDocument/didChange` is implemented vis-lspc is hardly usable. +But if you are brave there are some default key bindings: + + Normal mode: + <F2> - start a language server for win.syntax + <F3> - open win.file with a running language server + <C-]> - jump to the definition of the symbol under the main cursor + <C-t> - go back in the jump history + Normal and Insert mode: + <C- > - get completions + +## Requirements + +* vis must be compiled with the Lua [communicate API](https://github.com/martanne/vis/pull/675). +* Optional: the json implementation of your choice + * must be usable by calling `require('json')` + * must provide `json.encode, json.decode` + +## Installation + +1. Clone this repository into your vis plugins directory +2. Load the plugin in your `visrc.lua` with `require('plugins/vis-lspc')` + +## License + +All code except otherwise noted is licensed under the term of GPL-3. +See the LICENSE file for more details. +Our fallback json implementation in json.lua is NOT licensed under GPL-3. +It is taken from [here](https://gist.github.com/tylerneylon/59f4bcf316be525b30ab) +and is put into public domain by [Tyler Neylon](https://github.com/tylerneylon). diff --git a/init.lua b/init.lua new file mode 100644 index 0000000..59f0098 --- /dev/null +++ b/init.lua @@ -0,0 +1,645 @@ +-- Copyright (c) 2021 Florian Fischer. All rights reserved. +-- Use of this source code is governed by a MIT license found in the LICENSE file. +-- We require vis compiled with the communicate patch +if not vis.communicate then + vis:info('Error: language server support requires vis communicate patch') + return nil +end + +local function load_fallback_json() + local source_str = debug.getinfo(1, 'S').source:sub(2) + local script_path = source_str:match('(.*/)') + + return dofile(script_path .. 'json.lua') +end + +-- find a suitable json implementation +local json +if vis:module_exist('json') then + json = require('json') + if not json.encode or not json.decode then + json = load_fallback_json() + end +else + json = load_fallback_json() +end + +-- get vis's pid to pass it to the language servers +local vis_proc_file = assert(io.open('/proc/self/stat', 'r')) +local vis_pid = vis_proc_file:read('*n') +vis_proc_file:close() + +-- forward declaration of our client table +local lspc + +-- logging system +-- if lspc.logging is set to true the first call to lspc.log +-- will open the log file and replace lspc.log with the actual log function +local init_logging +do + local log_fd + local function log(msg) + log_fd:write(msg) + log_fd:flush() + end + + init_logging = function(msg) + if not lspc.logging then + return + end + + log_fd = assert(io.open('vis-lspc.log', 'w')) + lspc.log = log + + log(msg) + end +end + + +-- state of our language server client +lspc = { + running = {}, + name = 'vis-lspc', + version = '0.0.1', + logging = true, + log = init_logging, +} + +local clangd = {name = 'clangd', cmd = 'clangd'} + +-- map of known language servers per syntax +lspc.ls_map = {cpp = clangd, ansi_c = clangd} + +-- Document position code +-- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocumentPositionParams + +-- A document positions is defined by a file path and a (line, column) tuple +-- We use 1-based indices like vis and lua. +-- Note line and col numbers must be transformed into 0-based inices when communicating +-- with a language server + +local function path_to_uri(path) + return 'file://' .. path +end + +-- uri decode logic taken from +-- https://stackoverflow.com/questions/20405985/lua-decodeuri-luvit +local uri_decode_table = {} +for i = 0, 255 do + uri_decode_table[string.format('%02x', i)] = string.char(i) + uri_decode_table[string.format('%02X', i)] = string.char(i) +end + +local function decode_uri(s) + return (s:gsub('%%(%x%x)', uri_decode_table)) +end + +local function uri_to_path(uri) + return decode_uri(uri:gsub('file://', '')) +end + +-- convert LSP 0-based Position to vis position +local function lsp_pos_to_vis(pos) + return {line = pos.line + 1, col = pos.character + 1} +end + +-- convert 1-based vis position to LSP Position +local function vis_pos_to_lsp(pos) + return {line = pos.line - 1, character = pos.col - 1} +end + +-- convert our doc_pos to LSP TextDocumentPosition +local function vis_doc_pos_to_lsp(doc_pos) + return { + textDocument = {uri = path_to_uri(doc_pos.file)}, + position = vis_pos_to_lsp({line = doc_pos.line, col = doc_pos.col}), + } +end + +-- convert LSP TextDocumentPosition to our doc_pos +local function lsp_doc_pos_to_vis(doc_pos) + local pos = lsp_pos_to_vis(doc_pos.position) + return { + file = uri_to_path(doc_pos.textDocument.uri), + line = pos.line, + col = pos.col, + } +end + +-- get document position of the main curser +local function vis_get_doc_pos(win) + win = win or vis.win + return { + file = win.file.path, + line = win.selection.line, + col = win.selection.col, + } +end + +-- Support jumping between document positions +-- Open a document position in the active window +local vis_push_doc_pos +-- Restore the last text position in the active window +local vis_pop_doc_pos +do + -- stack of edited document positions + local doc_pos_stack = {} + + local function vis_goto_doc_pos(doc_pos) + vis:command('e ' .. doc_pos.file) + vis.win.selection:to(doc_pos.line, doc_pos.col) + end + + vis_push_doc_pos = function(doc_pos) + local old_doc_pos = {} + old_doc_pos.file = vis.win.file.path + old_doc_pos.line = vis.win.selection.line + old_doc_pos.col = vis.win.selection.col + + table.insert(doc_pos_stack, old_doc_pos) + vis_goto_doc_pos(doc_pos) + end + + vis_pop_doc_pos = function() + local last_doc_pos = table.remove(doc_pos_stack) + if not last_doc_pos then + return + end + vis_goto_doc_pos(last_doc_pos) + + -- reopen possibly closed file + vis:command('lspc-open') + end +end + +vis:command_register('lspc-back', function() + vis_pop_doc_pos() +end) + +-- apply a textEdit received from the language server +local function vis_apply_textEdit(win, file, textEdit) + assert(win.file == file) + + local start_pos = lsp_pos_to_vis(textEdit.range.start) + local end_pos = lsp_pos_to_vis(textEdit.range['end']) + + -- convert the LSP range into a vis range + -- this destroys the current selection but we change it after the edit anyway + win.selection.anchored = false + win.selection:to(start_pos.line, start_pos.col) + win.selection.anchored = true + win.selection:to(end_pos.line, end_pos.col - 1) + local range = win.selection.range + + file:delete(range) + file:insert(range.start, textEdit.newText) + + win.selection.anchored = false + win.selection.pos = range.start + string.len(textEdit.newText) + + win:draw() +end + +-- send a rpc message to a language server +local function ls_rpc(ls, req) + req.jsonrpc = '2.0' + + local content_part = json.encode(req) + local content_len = string.len(content_part) + + local header_part = 'Content-Length: ' .. tostring(content_len) + local msg = header_part .. '\r\n\r\n' .. content_part + lspc.log('LSPC Sending: ' .. msg .. '\n') + + ls.fd:write(msg) + ls.fd:flush() +end + +-- send a rpc method call to a language server +local function ls_call_method(ls, method, params, win) + local id = ls.id + ls.id = ls.id + 1 + + local req = {id = id, method = method, params = params} + ls.inflight[id] = req + + ls_rpc(ls, req) + -- remember the current window to apply the effects of a + -- method call in the original window + ls.inflight[id].win = win +end + +-- send a rpc notification to a language server +local function ls_send_notification(ls, method, params) + ls_rpc(ls, {method = method, params = params}) +end + +local function lspc_handle_goto_method_response(method, result) + if not result or next(result) == nil then + vis:info('LSPC Warning: ' .. method .. ' found no results') + return + end + + local location + -- result is no plain Location -> it must be Location[] + if not result.uri then + -- Use the first result. TODO: smarter result selection + location = result[1] + else + location = result + end + assert(location) + + local lsp_doc_pos = { + textDocument = {uri = location.uri}, + position = { + line = location.range.start.line, + character = location.range.start.character, + }, + } + + vis_push_doc_pos(lsp_doc_pos_to_vis(lsp_doc_pos)) +end + +local function lspc_handle_completion_method_response(win, result) + if not result or not result.items then + vis:info('LSPC Warning: no completion available') + return + end + + local completions = result + if result.isIncomplete ~= nil then + completions = result.items + end + + local vis_menu_input = '' + for _, completion in ipairs(completions) do + vis_menu_input = vis_menu_input .. completion.label .. '\n' + end + + -- select a completion + local completion = nil + local cmd = 'printf "' .. vis_menu_input .. '" | vis-menu' + local status, selection = vis:pipe(win.file, {start = 0, finish = 0}, cmd) + if status == 0 then + -- trim newline from selection + selection = selection:sub(1, -2) + + for _, item in ipairs(completions) do + if selection == item.label then + completion = item + break + end + end + + assert(completion) + + vis_apply_textEdit(win, win.file, completion.textEdit) + end +end + +-- method response dispatcher +local function ls_handle_method_response(ls, method_response) + local req = assert(ls.inflight[method_response.id]) + local win = req.win + + local method = req.method + local result = method_response.result + -- LuaFormatter off + if method == 'textDocument/definition' or + method == 'textDocument/declaration' or + method == 'textDocument/typeDefinition' or + method == 'textDocument/implementation' then + -- LuaFormatter on + lspc_handle_goto_method_response(method, result) + + elseif method == 'initialize' then + ls.initialized = true + ls.capabilities = result.capabilities + ls_send_notification(ls, 'initialized') + + elseif method == 'textDocument/completion' then + lspc_handle_completion_method_response(win, result) + + elseif method == 'shutdown' then + ls_send_notification(ls, 'exit') + ls.fd:close() + + -- remove the ls from lspc.running + for syntax, rls in pairs(lspc.running) do + if ls == rls then + lspc.running[syntax] = nil + break + end + end + else + vis:info('Warning: received unknown method ' .. method) + end + + ls.inflight[method_response.id] = nil +end + +local function ls_handle_notification(ls, notification) -- luacheck: no unused args +end + +-- dispatch between a method response and a notification from the server +local function ls_handle_msg(ls, response) + if response.id then + ls_handle_method_response(ls, response) + else + ls_handle_notification(ls, response) + end +end + +-- Parse the data send by the language server +-- Note the chunks received may not end with the end of a message. +-- In the worst case a data chunk contains two partial messages on at the beginning +-- and one at the end +local function ls_recv_data(ls, data) + -- new message received + if ls.partial_response.len == 0 then + lspc.log('LSPC: parse new message') + local header = data:match('^Content%-Length: %d+') + ls.partial_response.exp_len = tonumber(header:match('%d+')) + local _, content_start = data:find('\r\n\r\n') + + ls.partial_response.msg = data:sub(content_start + 1) + ls.partial_response.len = string.len(ls.partial_response.msg) + + else -- try to complete partial received message + lspc.log('LSPC: parse message continuation') + ls.partial_response.msg = ls.partial_response.msg .. data + ls.partial_response.len = ls.partial_response.len + string.len(data) + end + + -- received message not complete yet + if ls.partial_response.len < ls.partial_response.exp_len then + return + end + + local complete_msg = ls.partial_response.msg:sub(1, + ls.partial_response.exp_len) + + lspc.log('LSPC: handling complete message:\n' .. complete_msg .. '\n') + local resp = json.decode(complete_msg) + ls_handle_msg(ls, resp) + + local leftover = ls.partial_response.len - ls.partial_response.exp_len + + if leftover > 0 then + local leftover_data = ls.partial_response.msg:sub( + ls.partial_response.exp_len + 1) + lspc.log('LSPC: parse leftover:\n"' .. leftover_data .. '"\n') + + ls.partial_response.exp_len = 0 + ls.partial_response.len = 0 + ls_recv_data(ls, leftover_data) + end + + ls.partial_response.exp_len = 0 + ls.partial_response.len = 0 +end + +-- check if a language server is running and register file as open +local function lspc_get_usable_ls(syntax) + local ls = lspc.running[syntax] + if not ls then + vis:info('Error: No language server running for ' .. syntax) + return nil + end + + if not ls.initialized then + vis:info('Error: Language server not initialized yet. Please try again') + return nil + end + + return ls +end + +local function lspc_close(ls, file) + ls_send_notification(ls, 'textDocument/didClose', + {textDocument = {uri = path_to_uri(file.path)}}) + ls.open_files[file.path] = nil +end + +vis:command_register('lspc-close', function(_, _, win) + local ls = lspc_get_usable_ls(win.syntax) + + lspc_close(ls, win.file) +end) + +-- register a file as open with a language server and setup a close and save event handlers +-- A file must be opened before any textDocument functions can be used with it. +local function lspc_open(ls, win, file) + local params = { + textDocument = { + uri = 'file://' .. file.path, + languageId = win.syntax, + version = 0, + text = file:content(0, file.size), + }, + } + + ls.open_files[file.path] = {file = file, version = 0} + ls_send_notification(ls, 'textDocument/didOpen', params) + + -- TODO: implement textDocument/didChange + + vis.events.subscribe(vis.events.FILE_CLOSE, function(file) + for _, ls in pairs(lspc.running) do + if ls.open_files[file.path] then + lspc_close(ls, file) + end + end + end) + + -- the server is interested in didSave notifications + if ls.capabilities.textDocumentSync.save then + vis.events.subscribe(vis.events.FILE_SAVE_POST, function(file, path) + for _, ls in pairs(lspc.running) do + if ls.open_files[file.path] then + local params = {textDocument = {uri = path_to_uri(path)}} + ls_send_notification(ls, 'textDocument/didSave', params) + end + end + end) + end + +end + +vis:command_register('lspc-open', function(_, _, win) + local ls = lspc_get_usable_ls(win.syntax) + + if ls.open_files[win.file.path] then + return + end + + lspc_open(ls, win, win.file) +end) + +-- Initiate the shutdown of a language server +-- Sending the exit notification and closing the file handle are done in +-- the shutdown response handler. +local function ls_shutdown_server(ls) + ls_call_method(ls, 'shutdown', nil) +end + +vis:command_register('lspc-shutdown-server', function(argv, _, win) + local ls = lspc_get_usable_ls(argv[1] or win.syntax) + if not ls then + return + end + + ls_shutdown_server(ls) +end) + +local function ls_start_server(syntax) + if lspc.running[syntax] then + vis:info('Error: Already a language server running for ' .. syntax) + return + end + + local ls_conf = lspc.ls_map[syntax] + if not ls_conf then + vis:info('Error: No language server available for ' .. syntax) + return + end + + local ls = { + name = ls_conf.name, + initialized = false, + id = 0, + inflight = {}, + open_files = {}, + partial_response = {exp_len = 0, len = 0, response = nil}, + } + + ls.fd = vis:communicate(ls_conf.name, ls_conf.cmd) + + lspc.running[syntax] = ls + + -- register the response handler + vis.events.subscribe(vis.events.PROCESS_RESPONSE, function(name, msg, event) + if name ~= ls.name then + return + end + + if event == 'EXIT' or event == 'SIGNAL' then + if event == 'EXIT' then + vis:info('language server exited with: ' .. msg) + else + vis:info('language server received signal: ' .. msg) + end + + ls.running[syntax] = nil + return + end + + lspc.log('LS response(' .. event .. '): ' .. msg .. '\n') + if event == 'STDERR' then + return + end + + ls_recv_data(ls, msg) + end) + + local params = { + processID = vis_pid, + client = {name = lspc.name, version = lspc.version}, + rootUri = nil, + capabilities = {}, + } + + ls_call_method(ls, 'initialize', params) + + return ls +end + +vis:command_register('lspc-start-server', function(argv, _, win) + ls_start_server(argv[1] or win.syntax) +end) + +local function lspc_method_textDocumentPositionParams(ls, method, win) + -- check if the language server has a provider for this method + if not ls.capabilities[method .. 'Provider'] then + vis:info( + 'LPSC Error: language server ' .. ls.name .. ' does not provide ' .. + method) + return + end + + if not ls.open_files[win.file.path] then + lspc_open(ls, win, win.file) + end + + local params = vis_doc_pos_to_lsp(vis_get_doc_pos(win)) + + ls_call_method(ls, 'textDocument/' .. method, params, win) +end + +local function lspc_declaration(ls, win) + lspc_method_textDocumentPositionParams(ls, 'declaration', win) +end + +local function lspc_definition(ls, win) + lspc_method_textDocumentPositionParams(ls, 'definition', win) +end + +local function lspc_typeDefinition(ls, win) + lspc_method_textDocumentPositionParams(ls, 'typeDefinition', win) +end + +local function lspc_implementation(ls, win) + lspc_method_textDocumentPositionParams(ls, 'implementation', win) +end + +local function lspc_completion(ls, win) + lspc_method_textDocumentPositionParams(ls, 'completion', win) +end + +local lspc_methods = { + declaration = lspc_declaration, + definition = lspc_definition, + typeDefinition = lspc_typeDefinition, + implementation = lspc_implementation, + completion = lspc_completion, +} + +for name, func in pairs(lspc_methods) do + vis:command_register('lspc-' .. name, function(_, _, win, selection) + local ls = lspc_get_usable_ls(win.syntax, win.file) + if not ls then + return + end + + func(ls, win, selection) + end) +end + +-- default bindings +vis:map(vis.modes.NORMAL, '<F2>', function() + vis:command('lspc-start-server') +end) + +vis:map(vis.modes.NORMAL, '<F3>', function() + vis:command('lspc-open') +end) + +vis:map(vis.modes.NORMAL, '<C-]>', function() + vis:command('lspc-definition') +end) + +vis:map(vis.modes.NORMAL, '<C-t>', function() + vis:command('lspc-back') +end) + +vis:map(vis.modes.NORMAL, '<C- >', function() + vis:command('lspc-completion') +end) + +vis:map(vis.modes.INSERT, '<C- >', function() + vis:command('lspc-completion') + vis.mode = vis.modes.INSERT +end) + +return lspc diff --git a/json.lua b/json.lua new file mode 100644 index 0000000..ede894a --- /dev/null +++ b/json.lua @@ -0,0 +1,194 @@ +--[[ json.lua + +A compact pure-Lua JSON library. +The main functions are: json.encode, json.decode. + +## json.encode: + +This expects the following to be true of any tables being encoded: + * They only have string or number keys. Number keys must be represented as + strings in json; this is part of the json spec. + * They are not recursive. Such a structure cannot be specified in json. + +A Lua table is considered to be an array if and only if its set of keys is a +consecutive sequence of positive integers starting at 1. Arrays are encoded like +so: `[2, 3, false, "hi"]`. Any other type of Lua table is encoded as a json +object, encoded like so: `{"key1": 2, "key2": false}`. + +Because the Lua nil value cannot be a key, and as a table value is considerd +equivalent to a missing key, there is no way to express the json "null" value in +a Lua table. The only way this will output "null" is if your entire input obj is +nil itself. + +An empty Lua table, {}, could be considered either a json object or array - +it's an ambiguous edge case. We choose to treat this as an object as it is the +more general type. + +To be clear, none of the above considerations is a limitation of this code. +Rather, it is what we get when we completely observe the json specification for +as arbitrary a Lua object as json is capable of expressing. + +## json.decode: + +This function parses json, with the exception that it does not pay attention to +\u-escaped unicode code points in strings. + +It is difficult for Lua to return null as a value. In order to prevent the loss +of keys with a null value in a json string, this function uses the one-off +table value json.null (which is just an empty table) to indicate null values. +This way you can check if a value is null with the conditional +`val == json.null`. + +If you have control over the data and are using Lua, I would recommend just +avoiding null values in your data to begin with. + +--]] + + +local json = {} + + +-- Internal functions. + +local function kind_of(obj) + if type(obj) ~= 'table' then return type(obj) end + local i = 1 + for _ in pairs(obj) do + if obj[i] ~= nil then i = i + 1 else return 'table' end + end + if i == 1 then return 'table' else return 'array' end +end + +local function escape_str(s) + local in_char = {'\\', '"', '/', '\b', '\f', '\n', '\r', '\t'} + local out_char = {'\\', '"', '/', 'b', 'f', 'n', 'r', 't'} + for i, c in ipairs(in_char) do + s = s:gsub(c, '\\' .. out_char[i]) + end + return s +end + +-- Returns pos, did_find; there are two cases: +-- 1. Delimiter found: pos = pos after leading space + delim; did_find = true. +-- 2. Delimiter not found: pos = pos after leading space; did_find = false. +-- This throws an error if err_if_missing is true and the delim is not found. +local function skip_delim(str, pos, delim, err_if_missing) + pos = pos + #str:match('^%s*', pos) + if str:sub(pos, pos) ~= delim then + if err_if_missing then + error('Expected ' .. delim .. ' near position ' .. pos) + end + return pos, false + end + return pos + 1, true +end + +-- Expects the given pos to be the first character after the opening quote. +-- Returns val, pos; the returned pos is after the closing quote character. +local function parse_str_val(str, pos, val) + val = val or '' + local early_end_error = 'End of input found while parsing string.' + if pos > #str then error(early_end_error) end + local c = str:sub(pos, pos) + if c == '"' then return val, pos + 1 end + if c ~= '\\' then return parse_str_val(str, pos + 1, val .. c) end + -- We must have a \ character. + local esc_map = {b = '\b', f = '\f', n = '\n', r = '\r', t = '\t'} + local nextc = str:sub(pos + 1, pos + 1) + if not nextc then error(early_end_error) end + return parse_str_val(str, pos + 2, val .. (esc_map[nextc] or nextc)) +end + +-- Returns val, pos; the returned pos is after the number's final character. +local function parse_num_val(str, pos) + local num_str = str:match('^-?%d+%.?%d*[eE]?[+-]?%d*', pos) + local val = tonumber(num_str) + if not val then error('Error parsing number at position ' .. pos .. '.') end + return val, pos + #num_str +end + + +-- Public values and functions. + +function json.encode(obj, as_key) + local s = {} -- We'll build the string as an array of strings to be concatenated. + local kind = kind_of(obj) -- This is 'array' if it's an array or type(obj) otherwise. + if kind == 'array' then + if as_key then error('Can\'t encode array as key.') end + s[#s + 1] = '[' + for i, val in ipairs(obj) do + if i > 1 then s[#s + 1] = ', ' end + s[#s + 1] = json.encode(val) + end + s[#s + 1] = ']' + elseif kind == 'table' then + if as_key then error('Can\'t encode table as key.') end + s[#s + 1] = '{' + for k, v in pairs(obj) do + if #s > 1 then s[#s + 1] = ', ' end + s[#s + 1] = json.encode(k, true) + s[#s + 1] = ':' + s[#s + 1] = json.encode(v) + end + s[#s + 1] = '}' + elseif kind == 'string' then + return '"' .. escape_str(obj) .. '"' + elseif kind == 'number' then + if as_key then return '"' .. tostring(obj) .. '"' end + return tostring(obj) + elseif kind == 'boolean' then + return tostring(obj) + elseif kind == 'nil' then + return 'null' + else + error('Unjsonifiable type: ' .. kind .. '.') + end + return table.concat(s) +end + +json.null = {} -- This is a one-off table to represent the null value. + +function json.decode(str, pos, end_delim) + pos = pos or 1 + if pos > #str then error('Reached unexpected end of input.') end + local pos = pos + #str:match('^%s*', pos) -- Skip whitespace. + local first = str:sub(pos, pos) + if first == '{' then -- Parse an object. + local obj, key, delim_found = {}, true, true + pos = pos + 1 + while true do + key, pos = json.decode(str, pos, '}') + if key == nil then return obj, pos end + if not delim_found then error('Comma missing between object items.') end + pos = skip_delim(str, pos, ':', true) -- true -> error if missing. + obj[key], pos = json.decode(str, pos) + pos, delim_found = skip_delim(str, pos, ',') + end + elseif first == '[' then -- Parse an array. + local arr, val, delim_found = {}, true, true + pos = pos + 1 + while true do + val, pos = json.decode(str, pos, ']') + if val == nil then return arr, pos end + if not delim_found then error('Comma missing between array items.') end + arr[#arr + 1] = val + pos, delim_found = skip_delim(str, pos, ',') + end + elseif first == '"' then -- Parse a string. + return parse_str_val(str, pos + 1) + elseif first == '-' or first:match('%d') then -- Parse a number. + return parse_num_val(str, pos) + elseif first == end_delim then -- End of an object or array. + return nil, pos + 1 + else -- Parse true, false, or null. + local literals = {['true'] = true, ['false'] = false, ['null'] = json.null} + for lit_str, lit_val in pairs(literals) do + local lit_end = pos + #lit_str - 1 + if str:sub(pos, lit_end) == lit_str then return lit_val, lit_end + 1 end + end + local pos_info_str = 'position ' .. pos .. ': ' .. str:sub(pos, pos + 10) + error('Invalid json syntax starting at ' .. pos_info_str) + end +end + +return json |