sc3-rom-dump/rom/modules/main/cc/pretty.lua

527 lines
18 KiB
Lua

-- SPDX-FileCopyrightText: 2020 The CC: Tweaked Developers
--
-- SPDX-License-Identifier: MPL-2.0
--[[- A pretty printer for rendering data structures in an aesthetically
pleasing manner.
In order to display something using [`cc.pretty`], you build up a series of
[documents][`Doc`]. These behave a little bit like strings; you can concatenate
them together and then print them to the screen.
However, documents also allow you to control how they should be printed. There
are several functions (such as [`nest`] and [`group`]) which allow you to control
the "layout" of the document. When you come to display the document, the 'best'
(most compact) layout is used.
The structure of this module is based on [A Prettier Printer][prettier].
[prettier]: https://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf "A Prettier Printer"
@module cc.pretty
@since 1.87.0
@usage Print a table to the terminal
local pretty = require "cc.pretty"
pretty.pretty_print({ 1, 2, 3 })
@usage Build a custom document and display it
local pretty = require "cc.pretty"
pretty.print(pretty.group(pretty.text("hello") .. pretty.space_line .. pretty.text("world")))
]]
local expect = require "cc.expect"
local expect, field = expect.expect, expect.field
local type, getmetatable, setmetatable, colours, str_write, tostring = type, getmetatable, setmetatable, colours, write, tostring
local debug_info, debug_local = debug.getinfo, debug.getlocal
--- [`table.insert`] alternative, but with the length stored inline.
local function append(out, value)
local n = out.n + 1
out[n], out.n = value, n
end
--- A document containing formatted text, with multiple possible layouts.
--
-- Documents effectively represent a sequence of strings in alternative layouts,
-- which we will try to print in the most compact form necessary.
--
-- @type Doc
local Doc = { }
local function mk_doc(tbl) return setmetatable(tbl, Doc) end
--- An empty document.
local empty = mk_doc({ tag = "nil" })
--- A document with a single space in it.
local space = mk_doc({ tag = "text", text = " " })
--- A line break. When collapsed with [`group`], this will be replaced with [`empty`].
local line = mk_doc({ tag = "line", flat = empty })
--- A line break. When collapsed with [`group`], this will be replaced with [`space`].
local space_line = mk_doc({ tag = "line", flat = space })
local text_cache = { [""] = empty, [" "] = space, ["\n"] = space_line }
local function mk_text(text, colour)
return text_cache[text] or setmetatable({ tag = "text", text = text, colour = colour }, Doc)
end
--- Create a new document from a string.
--
-- If your string contains multiple lines, [`group`] will flatten the string
-- into a single line, with spaces between each line.
--
-- @tparam string text The string to construct a new document with.
-- @tparam[opt] number colour The colour this text should be printed with. If not given, we default to the current
-- colour.
-- @treturn Doc The document with the provided text.
-- @usage Write some blue text.
--
-- local pretty = require "cc.pretty"
-- pretty.print(pretty.text("Hello!", colours.blue))
local function text(text, colour)
expect(1, text, "string")
expect(2, colour, "number", "nil")
local cached = text_cache[text]
if cached then return cached end
local new_line = text:find("\n", 1)
if not new_line then return mk_text(text, colour) end
-- Split the string by "\n". With a micro-optimisation to skip empty strings.
local doc = setmetatable({ tag = "concat", n = 0 }, Doc)
if new_line ~= 1 then append(doc, mk_text(text:sub(1, new_line - 1), colour)) end
new_line = new_line + 1
while true do
local next_line = text:find("\n", new_line)
append(doc, space_line)
if not next_line then
if new_line <= #text then append(doc, mk_text(text:sub(new_line), colour)) end
return doc
else
if new_line <= next_line - 1 then
append(doc, mk_text(text:sub(new_line, next_line - 1), colour))
end
new_line = next_line + 1
end
end
end
--- Concatenate several documents together. This behaves very similar to string concatenation.
--
-- @tparam Doc|string ... The documents to concatenate.
-- @treturn Doc The concatenated documents.
-- @usage
-- local pretty = require "cc.pretty"
-- local doc1, doc2 = pretty.text("doc1"), pretty.text("doc2")
-- print(pretty.concat(doc1, " - ", doc2))
-- print(doc1 .. " - " .. doc2) -- Also supports ..
local function concat(...)
local args = table.pack(...)
for i = 1, args.n do
if type(args[i]) == "string" then args[i] = text(args[i]) end
if getmetatable(args[i]) ~= Doc then expect(i, args[i], "document") end
end
if args.n == 0 then return empty end
if args.n == 1 then return args[1] end
args.tag = "concat"
return setmetatable(args, Doc)
end
Doc.__concat = concat --- @local
--- Indent later lines of the given document with the given number of spaces.
--
-- For instance, nesting the document
-- ```txt
-- foo
-- bar
-- ```
-- by two spaces will produce
-- ```txt
-- foo
-- bar
-- ```
--
-- @tparam number depth The number of spaces with which the document should be indented.
-- @tparam Doc doc The document to indent.
-- @treturn Doc The nested document.
-- @usage
-- local pretty = require "cc.pretty"
-- print(pretty.nest(2, pretty.text("foo\nbar")))
local function nest(depth, doc)
expect(1, depth, "number")
if getmetatable(doc) ~= Doc then expect(2, doc, "document") end
if depth <= 0 then error("depth must be a positive number", 2) end
return setmetatable({ tag = "nest", depth = depth, doc }, Doc)
end
local function flatten(doc)
if doc.flat then return doc.flat end
local kind = doc.tag
if kind == "nil" or kind == "text" then
return doc
elseif kind == "concat" then
local out = setmetatable({ tag = "concat", n = doc.n }, Doc)
for i = 1, doc.n do out[i] = flatten(doc[i]) end
doc.flat, out.flat = out, out -- cache the flattened node
return out
elseif kind == "nest" then
return flatten(doc[1])
elseif kind == "group" then
return doc[1]
else
error("Unknown doc " .. kind)
end
end
--- Builds a document which is displayed on a single line if there is enough
-- room, or as normal if not.
--
-- @tparam Doc doc The document to group.
-- @treturn Doc The grouped document.
-- @usage Uses group to show things being displayed on one or multiple lines.
--
-- local pretty = require "cc.pretty"
-- local doc = pretty.group("Hello" .. pretty.space_line .. "World")
-- print(pretty.render(doc, 5)) -- On multiple lines
-- print(pretty.render(doc, 20)) -- Collapsed onto one.
local function group(doc)
if getmetatable(doc) ~= Doc then expect(1, doc, "document") end
if doc.tag == "group" then return doc end -- Skip if already grouped.
local flattened = flatten(doc)
if flattened == doc then return doc end -- Also skip if flattening does nothing.
return setmetatable({ tag = "group", flattened, doc }, Doc)
end
local function get_remaining(doc, width)
local kind = doc.tag
if kind == "nil" or kind == "line" then
return width
elseif kind == "text" then
return width - #doc.text
elseif kind == "concat" then
for i = 1, doc.n do
width = get_remaining(doc[i], width)
if width < 0 then break end
end
return width
elseif kind == "group" or kind == "nest" then
return get_remaining(kind[1])
else
error("Unknown doc " .. kind)
end
end
--- Display a document on the terminal.
--
-- @tparam Doc doc The document to render
-- @tparam[opt=0.6] number ribbon_frac The maximum fraction of the width that we should write in.
local function write(doc, ribbon_frac)
if getmetatable(doc) ~= Doc then expect(1, doc, "document") end
expect(2, ribbon_frac, "number", "nil")
local term = term
local width, height = term.getSize()
local ribbon_width = (ribbon_frac or 0.6) * width
if ribbon_width < 0 then ribbon_width = 0 end
if ribbon_width > width then ribbon_width = width end
local def_colour = term.getTextColour()
local current_colour = def_colour
local function go(doc, indent, col)
local kind = doc.tag
if kind == "nil" then
return col
elseif kind == "text" then
local doc_colour = doc.colour or def_colour
if doc_colour ~= current_colour then
term.setTextColour(doc_colour)
current_colour = doc_colour
end
str_write(doc.text)
return col + #doc.text
elseif kind == "line" then
local _, y = term.getCursorPos()
if y < height then
term.setCursorPos(indent + 1, y + 1)
else
term.scroll(1)
term.setCursorPos(indent + 1, height)
end
return indent
elseif kind == "concat" then
for i = 1, doc.n do col = go(doc[i], indent, col) end
return col
elseif kind == "nest" then
return go(doc[1], indent + doc.depth, col)
elseif kind == "group" then
if get_remaining(doc[1], math.min(width, ribbon_width + indent) - col) >= 0 then
return go(doc[1], indent, col)
else
return go(doc[2], indent, col)
end
else
error("Unknown doc " .. kind)
end
end
local col = math.max(term.getCursorPos() - 1, 0)
go(doc, 0, col)
if current_colour ~= def_colour then term.setTextColour(def_colour) end
end
--- Display a document on the terminal with a trailing new line.
--
-- @tparam Doc doc The document to render.
-- @tparam[opt=0.6] number ribbon_frac The maximum fraction of the width that we should write in.
local function print(doc, ribbon_frac)
if getmetatable(doc) ~= Doc then expect(1, doc, "document") end
expect(2, ribbon_frac, "number", "nil")
write(doc, ribbon_frac)
str_write("\n")
end
--- Render a document, converting it into a string.
--
-- @tparam Doc doc The document to render.
-- @tparam[opt] number width The maximum width of this document. Note that long strings will not be wrapped to fit
-- this width - it is only used for finding the best layout.
-- @tparam[opt=0.6] number ribbon_frac The maximum fraction of the width that we should write in.
-- @treturn string The rendered document as a string.
local function render(doc, width, ribbon_frac)
if getmetatable(doc) ~= Doc then expect(1, doc, "document") end
expect(2, width, "number", "nil")
expect(3, ribbon_frac, "number", "nil")
local ribbon_width
if width then
ribbon_width = (ribbon_frac or 0.6) * width
if ribbon_width < 0 then ribbon_width = 0 end
if ribbon_width > width then ribbon_width = width end
end
local out = { n = 0 }
local function go(doc, indent, col)
local kind = doc.tag
if kind == "nil" then
return col
elseif kind == "text" then
append(out, doc.text)
return col + #doc.text
elseif kind == "line" then
append(out, "\n" .. (" "):rep(indent))
return indent
elseif kind == "concat" then
for i = 1, doc.n do col = go(doc[i], indent, col) end
return col
elseif kind == "nest" then
return go(doc[1], indent + doc.depth, col)
elseif kind == "group" then
if not width or get_remaining(doc[1], math.min(width, ribbon_width + indent) - col) >= 0 then
return go(doc[1], indent, col)
else
return go(doc[2], indent, col)
end
else
error("Unknown doc " .. kind)
end
end
go(doc, 0, 0)
return table.concat(out, "", 1, out.n)
end
Doc.__tostring = render --- @local
local keywords = {
["and"] = true, ["break"] = true, ["do"] = true, ["else"] = true,
["elseif"] = true, ["end"] = true, ["false"] = true, ["for"] = true,
["function"] = true, ["if"] = true, ["in"] = true, ["local"] = true,
["nil"] = true, ["not"] = true, ["or"] = true, ["repeat"] = true, ["return"] = true,
["then"] = true, ["true"] = true, ["until"] = true, ["while"] = true,
}
local comma = text(",")
local braces = text("{}")
local obrace, cbrace = text("{"), text("}")
local obracket, cbracket = text("["), text("] = ")
local function key_compare(a, b)
local ta, tb = type(a), type(b)
if ta == "string" then return tb ~= "string" or a < b
elseif tb == "string" then return false
end
if ta == "number" then return tb ~= "number" or a < b end
return false
end
local function show_function(fn, options)
local info = debug_info and debug_info(fn, "Su")
-- Include function source position if available
local name
if options.function_source and info and info.short_src and info.linedefined and info.linedefined >= 1 then
name = "function<" .. info.short_src .. ":" .. info.linedefined .. ">"
else
name = tostring(fn)
end
-- Include arguments if a Lua function and if available. Lua will report "C"
-- functions as variadic.
if options.function_args and info and info.what == "Lua" and info.nparams and debug_local then
local args = {}
for i = 1, info.nparams do args[i] = debug_local(fn, i) or "?" end
if info.isvararg then args[#args + 1] = "..." end
name = name .. "(" .. table.concat(args, ", ") .. ")"
end
return name
end
local function pretty_impl(obj, options, tracking)
local obj_type = type(obj)
if obj_type == "string" then
local formatted = ("%q"):format(obj):gsub("\\\n", "\\n")
return text(formatted, colours.red)
elseif obj_type == "number" then
return text(tostring(obj), colours.magenta)
elseif obj_type == "function" then
return text(show_function(obj, options), colours.lightGrey)
elseif obj_type ~= "table" or tracking[obj] then
return text(tostring(obj), colours.lightGrey)
elseif getmetatable(obj) ~= nil and getmetatable(obj).__tostring then
return text(tostring(obj))
elseif next(obj) == nil then
return braces
else
tracking[obj] = true
local doc = setmetatable({ tag = "concat", n = 1, space_line }, Doc)
local length, keys, keysn = #obj, {}, 1
for k in pairs(obj) do
if type(k) ~= "number" or k % 1 ~= 0 or k < 1 or k > length then
keys[keysn], keysn = k, keysn + 1
end
end
table.sort(keys, key_compare)
for i = 1, length do
if i > 1 then append(doc, comma) append(doc, space_line) end
append(doc, pretty_impl(obj[i], options, tracking))
end
for i = 1, keysn - 1 do
if i > 1 or length >= 1 then append(doc, comma) append(doc, space_line) end
local k = keys[i]
local v = obj[k]
if type(k) == "string" and not keywords[k] and k:match("^[%a_][%a%d_]*$") then
append(doc, text(k .. " = "))
append(doc, pretty_impl(v, options, tracking))
else
append(doc, obracket)
append(doc, pretty_impl(k, options, tracking))
append(doc, cbracket)
append(doc, pretty_impl(v, options, tracking))
end
end
tracking[obj] = nil
return group(concat(obrace, nest(2, concat(table.unpack(doc, 1, doc.n))), space_line, cbrace))
end
end
--- Pretty-print an arbitrary object, converting it into a document.
--
-- This can then be rendered with [`write`] or [`print`].
--
-- @param obj The object to pretty-print.
-- @tparam[opt] { function_args = boolean, function_source = boolean } options
-- Controls how various properties are displayed.
-- - `function_args`: Show the arguments to a function if known (`false` by default).
-- - `function_source`: Show where the function was defined, instead of
-- `function: xxxxxxxx` (`false` by default).
-- @treturn Doc The object formatted as a document.
-- @changed 1.88.0 Added `options` argument.
-- @usage Display a table on the screen
--
-- local pretty = require "cc.pretty"
-- pretty.print(pretty.pretty({ 1, 2, 3 }))
-- @see pretty_print for a shorthand to prettify and print an object.
local function pretty(obj, options)
expect(2, options, "table", "nil")
options = options or {}
local actual_options = {
function_source = field(options, "function_source", "boolean", "nil") or false,
function_args = field(options, "function_args", "boolean", "nil") or false,
}
return pretty_impl(obj, actual_options, {})
end
--[[- A shortcut for calling [`pretty`] and [`print`] together.
@param obj The object to pretty-print.
@tparam[opt] { function_args = boolean, function_source = boolean } options
Controls how various properties are displayed.
- `function_args`: Show the arguments to a function if known (`false` by default).
- `function_source`: Show where the function was defined, instead of
`function: xxxxxxxx` (`false` by default).
@tparam[opt=0.6] number ribbon_frac The maximum fraction of the width that we should write in.
@usage Display a table on the screen.
local pretty = require "cc.pretty"
pretty.pretty_print({ 1, 2, 3 })
@see pretty
@see print
@since 1.99
]]
local function pretty_print(obj, options, ribbon_frac)
expect(2, options, "table", "nil")
options = options or {}
expect(3, ribbon_frac, "number", "nil")
return print(pretty(obj, options), ribbon_frac)
end
return {
empty = empty,
space = space,
line = line,
space_line = space_line,
text = text,
concat = concat,
nest = nest,
group = group,
write = write,
print = print,
render = render,
pretty = pretty,
pretty_print = pretty_print,
}