aboutsummaryrefslogtreecommitdiff
path: root/.config/vis/plugins/vis-lspc/json.lua
diff options
context:
space:
mode:
authordacctal <dacctal@symlinx.net>2026-04-27 05:30:46 +0000
committerdacctal <dacctal@symlinx.net>2026-04-27 05:30:46 +0000
commitd33d907f53c50d323eca75c4bfc02ab5b989b30a (patch)
tree6888a2074338a723f0fde99b03b09fbab91a265f /.config/vis/plugins/vis-lspc/json.lua
parent89505535c652cd6f31a15df73293c6e90eaa852f (diff)
added bare pluginsHEADmaster
Diffstat (limited to '.config/vis/plugins/vis-lspc/json.lua')
-rw-r--r--.config/vis/plugins/vis-lspc/json.lua216
1 files changed, 216 insertions, 0 deletions
diff --git a/.config/vis/plugins/vis-lspc/json.lua b/.config/vis/plugins/vis-lspc/json.lua
new file mode 100644
index 0000000..876a889
--- /dev/null
+++ b/.config/vis/plugins/vis-lspc/json.lua
@@ -0,0 +1,216 @@
+--- Find or provide a suitable json module for vis-lspc.
+--
+-- @module json
+local json = {}
+
+--- Json modules to use if they are included in LUA_PATH.
+local json_impls = {'json', 'cjson', 'dkjson'}
+
+-- find a suitable json implementation
+for _, json_impl in ipairs(json_impls) do
+ if vis:module_exist(json_impl) then
+ json = require(json_impl)
+ if not json.encode or not json.decode then
+ json = nil
+ end
+
+ -- found a usable json implementation
+ if json then
+ return json
+ end
+ end
+end
+
+--[[ 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 json.null table can be used to encode the json "null" value.
+{key=json.null} will be encoded to `{"key":null}`.
+
+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.
+
+--]]
+
+-- Internal functions.
+
+local function kind_of(obj)
+ if obj == json.null then
+ return 'nil'
+ end
+ 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