--- /dev/null
+-------------------------------------------------------------------------------
+-- Copyright (c) 2006-2013 Fabien Fleutot and others.
+--
+-- All rights reserved.
+--
+-- This program and the accompanying materials are made available
+-- under the terms of the Eclipse Public License v1.0 which
+-- accompanies this distribution, and is available at
+-- http://www.eclipse.org/legal/epl-v10.html
+--
+-- This program and the accompanying materials are also made available
+-- under the terms of the MIT public license which accompanies this
+-- distribution, and is available at http://www.lua.org/license.html
+--
+-- Contributors:
+-- Fabien Fleutot - API and implementation
+--
+----------------------------------------------------------------------
+
+----------------------------------------------------------------------
+----------------------------------------------------------------------
+--
+-- Lua objects pretty-printer
+--
+----------------------------------------------------------------------
+----------------------------------------------------------------------
+
+local M = { }
+
+M.DEFAULT_CFG = {
+ hide_hash = false; -- Print the non-array part of tables?
+ metalua_tag = true; -- Use Metalua's backtick syntax sugar?
+ fix_indent = nil; -- If a number, number of indentation spaces;
+ -- If false, indent to the previous brace.
+ line_max = nil; -- If a number, tries to avoid making lines with
+ -- more than this number of chars.
+ initial_indent = 0; -- If a number, starts at this level of indentation
+ keywords = { }; -- Set of keywords which must not use Lua's field
+ -- shortcuts {["foo"]=...} -> {foo=...}
+}
+
+local function valid_id(cfg, x)
+ if type(x) ~= "string" then return false end
+ if not x:match "^[a-zA-Z_][a-zA-Z0-9_]*$" then return false end
+ if cfg.keywords and cfg.keywords[x] then return false end
+ return true
+end
+
+local __tostring_cache = setmetatable({ }, {__mode='k'})
+
+-- Retrieve the string produced by `__tostring` metamethod if present,
+-- return `false` otherwise. Cached in `__tostring_cache`.
+local function __tostring(x)
+ local the_string = __tostring_cache[x]
+ if the_string~=nil then return the_string end
+ local mt = getmetatable(x)
+ if mt then
+ local __tostring = mt.__tostring
+ if __tostring then
+ the_string = __tostring(x)
+ __tostring_cache[x] = the_string
+ return the_string
+ end
+ end
+ if x~=nil then __tostring_cache[x] = false end -- nil is an illegal key
+ return false
+end
+
+local xlen -- mutually recursive with `xlen_type`
+
+local xlen_cache = setmetatable({ }, {__mode='k'})
+
+-- Helpers for the `xlen` function
+local xlen_type = {
+ ["nil"] = function ( ) return 3 end;
+ number = function (x) return #tostring(x) end;
+ boolean = function (x) return x and 4 or 5 end;
+ string = function (x) return #string.format("%q",x) end;
+}
+
+function xlen_type.table (adt, cfg, nested)
+ local custom_string = __tostring(adt)
+ if custom_string then return #custom_string end
+
+ -- Circular referenced objects are printed with the plain
+ -- `tostring` function in nested positions.
+ if nested [adt] then return #tostring(adt) end
+ nested [adt] = true
+
+ local has_tag = cfg.metalua_tag and valid_id(cfg, adt.tag)
+ local alen = #adt
+ local has_arr = alen>0
+ local has_hash = false
+ local x = 0
+
+ if not cfg.hide_hash then
+ -- first pass: count hash-part
+ for k, v in pairs(adt) do
+ if k=="tag" and has_tag then
+ -- this is the tag -> do nothing!
+ elseif type(k)=="number" and k<=alen and math.fmod(k,1)==0 and k>0 then
+ -- array-part pair -> do nothing!
+ else
+ has_hash = true
+ if valid_id(cfg, k) then x=x+#k
+ else x = x + xlen (k, cfg, nested) + 2 end -- count surrounding brackets
+ x = x + xlen (v, cfg, nested) + 5 -- count " = " and ", "
+ end
+ end
+ end
+
+ for i = 1, alen do x = x + xlen (adt[i], nested) + 2 end -- count ", "
+
+ nested[adt] = false -- No more nested calls
+
+ if not (has_tag or has_arr or has_hash) then return 3 end
+ if has_tag then x=x+#adt.tag+1 end
+ if not (has_arr or has_hash) then return x end
+ if not has_hash and alen==1 and type(adt[1])~="table" then
+ return x-2 -- substract extraneous ", "
+ end
+ return x+2 -- count "{ " and " }", substract extraneous ", "
+end
+
+
+-- Compute the number of chars it would require to display the table
+-- on a single line. Helps to decide whether some carriage returns are
+-- required. Since the size of each sub-table is required many times,
+-- it's cached in [xlen_cache].
+xlen = function (x, cfg, nested)
+ -- no need to compute length for 1-line prints
+ if not cfg.line_max then return 0 end
+ nested = nested or { }
+ if x==nil then return #"nil" end
+ local len = xlen_cache[x]
+ if len then return len end
+ local f = xlen_type[type(x)]
+ if not f then return #tostring(x) end
+ len = f (x, cfg, nested)
+ xlen_cache[x] = len
+ return len
+end
+
+local function consider_newline(p, len)
+ if not p.cfg.line_max then return end
+ if p.current_offset + len <= p.cfg.line_max then return end
+ if p.indent < p.current_offset then
+ p:acc "\n"; p:acc ((" "):rep(p.indent))
+ p.current_offset = p.indent
+ end
+end
+
+local acc_value
+
+local acc_type = {
+ ["nil"] = function(p) p:acc("nil") end;
+ number = function(p, adt) p:acc (tostring (adt)) end;
+ string = function(p, adt) p:acc ((string.format ("%q", adt):gsub("\\\n", "\\n"))) end;
+ boolean = function(p, adt) p:acc (adt and "true" or "false") end }
+
+-- Indentation:
+-- * if `cfg.fix_indent` is set to a number:
+-- * add this number of space for each level of depth
+-- * return to the line as soon as it flushes things further left
+-- * if not, tabulate to one space after the opening brace.
+-- * as a result, it never saves right-space to return before first element
+
+function acc_type.table(p, adt)
+ if p.nested[adt] then p:acc(tostring(adt)); return end
+ p.nested[adt] = true
+
+ local has_tag = p.cfg.metalua_tag and valid_id(p.cfg, adt.tag)
+ local alen = #adt
+ local has_arr = alen>0
+ local has_hash = false
+
+ local previous_indent = p.indent
+
+ if has_tag then p:acc("`"); p:acc(adt.tag) end
+
+ local function indent(p)
+ if not p.cfg.fix_indent then p.indent = p.current_offset
+ else p.indent = p.indent + p.cfg.fix_indent end
+ end
+
+ -- First pass: handle hash-part
+ if not p.cfg.hide_hash then
+ for k, v in pairs(adt) do
+
+ if has_tag and k=='tag' then -- pass the 'tag' field
+ elseif type(k)=="number" and k<=alen and k>0 and math.fmod(k,1)==0 then
+ -- pass array-part keys (consecutive ints less than `#adt`)
+ else -- hash-part keys
+ if has_hash then p:acc ", " else -- 1st hash-part pair ever found
+ p:acc "{ "; indent(p)
+ end
+
+ -- Determine whether a newline is required
+ local is_id, expected_len=valid_id(p.cfg, k)
+ if is_id then expected_len=#k+xlen(v, p.cfg, p.nested)+#" = , "
+ else expected_len = xlen(k, p.cfg, p.nested)+xlen(v, p.cfg, p.nested)+#"[] = , " end
+ consider_newline(p, expected_len)
+
+ -- Print the key
+ if is_id then p:acc(k); p:acc " = " else
+ p:acc "["; acc_value (p, k); p:acc "] = "
+ end
+
+ acc_value (p, v) -- Print the value
+ has_hash = true
+ end
+ end
+ end
+
+ -- Now we know whether there's a hash-part, an array-part, and a tag.
+ -- Tag and hash-part are already printed if they're present.
+ if not has_tag and not has_hash and not has_arr then p:acc "{ }";
+ elseif has_tag and not has_hash and not has_arr then -- nothing, tag already in acc
+ else
+ assert (has_hash or has_arr) -- special case { } already handled
+ local no_brace = false
+ if has_hash and has_arr then p:acc ", "
+ elseif has_tag and not has_hash and alen==1 and type(adt[1])~="table" then
+ -- No brace required; don't print "{", remember not to print "}"
+ p:acc (" "); acc_value (p, adt[1]) -- indent= indent+(cfg.fix_indent or 0))
+ no_brace = true
+ elseif not has_hash then
+ -- Braces required, but not opened by hash-part handler yet
+ p:acc "{ "; indent(p)
+ end
+
+ -- 2nd pass: array-part
+ if not no_brace and has_arr then
+ local expected_len = xlen(adt[1], p.cfg, p.nested)
+ consider_newline(p, expected_len)
+ acc_value(p, adt[1]) -- indent+(cfg.fix_indent or 0)
+ for i=2, alen do
+ p:acc ", ";
+ consider_newline(p, xlen(adt[i], p.cfg, p.nested))
+ acc_value (p, adt[i]) --indent+(cfg.fix_indent or 0)
+ end
+ end
+ if not no_brace then p:acc " }" end
+ end
+ p.nested[adt] = false -- No more nested calls
+ p.indent = previous_indent
+end
+
+
+function acc_value(p, v)
+ local custom_string = __tostring(v)
+ if custom_string then p:acc(custom_string) else
+ local f = acc_type[type(v)]
+ if f then f(p, v) else p:acc(tostring(v)) end
+ end
+end
+
+
+-- FIXME: new_indent seems to be always nil?!s detection
+-- FIXME: accumulator function should be configurable,
+-- so that print() doesn't need to bufferize the whole string
+-- before starting to print.
+function M.tostring(t, cfg)
+
+ cfg = cfg or M.DEFAULT_CFG or { }
+
+ local p = {
+ cfg = cfg;
+ indent = 0;
+ current_offset = cfg.initial_indent or 0;
+ buffer = { };
+ nested = { };
+ acc = function(self, str)
+ table.insert(self.buffer, str)
+ self.current_offset = self.current_offset + #str
+ end;
+ }
+ acc_value(p, t)
+ return table.concat(p.buffer)
+end
+
+function M.print(...) return print(M.tostring(...)) end
+function M.sprintf(fmt, ...)
+ local args={...}
+ for i, v in pairs(args) do
+ local t=type(v)
+ if t=='table' then args[i]=M.tostring(v)
+ elseif t=='nil' then args[i]='nil' end
+ end
+ return string.format(fmt, unpack(args))
+end
+
+function M.printf(...) print(M.sprintf(...)) end
+
+return M
\ No newline at end of file
projects / metalua.git / blobdiff