Minetest-WorldEditAdditions/worldeditadditions/utils/parse/tokenise_commands.lua

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--- Uncomment these 2 lines to run in standalone mode
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-- worldeditadditions = { parse = { } }
-- function worldeditadditions.trim(str) return (str:gsub("^%s*(.-)%s*$", "%1")) end
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--- The main tokeniser. Splits the input string up into space separated tokens, except when said spaces are inside { curly braces }.
-- Note that the outermost set of curly braces are stripped.
-- @param str string The input string to tokenise.
-- @returns string[] A list of tokens
local function tokenise(str)
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if type(str) ~= "string" then return false, "Error: Expected input of type string." end
str = str:gsub("%s+", " ") -- Replace all runs of whitespace with a single space
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-- The resulting tokens
local result = {}
local nested_depth = 0 -- The nested depth inside { and } we're currently at
local nested_stack = {} -- Stack of starting positions of curly brace { } blocks
local scanpos = 1 -- The current position we're scanning
while scanpos <= #str do
-- Find the next character of interest
local nextpos = str:find("[%s{}]", scanpos)
-- If it's nil, then cleanup and return
if nextpos == nil then
if nested_depth > 0 then
-- Handle unclosed brace groups
return false, "Error: Unclosed brace group detected."
else
-- Make sure we catch any trailing parts
local str_trailing = str:sub(scanpos)
if #str_trailing then table.insert(result, str_trailing) end
return true, result
end
end
-- Extract the character in question
local char = str:sub(nextpos, nextpos)
if char == "}" then
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if nested_depth > 0 then
-- Decrease the nested depth
nested_depth = nested_depth - 1
-- Pop the start of this block off the stack and find this block's contents
local block_start = table.remove(nested_stack, #nested_stack)
local substr = str:sub(block_start, nextpos - 1)
if #substr > 0 and nested_depth == 0 then table.insert(result, substr) end
end
elseif char == "{" then
-- Increase the nested depth, and store this position on the stack for later
nested_depth = nested_depth + 1
table.insert(nested_stack, nextpos + 1)
else
-- It's a space! Extract a part, but only if the nested depth is 0 (i.e. we're not inside any braces).
local substr = str:sub(scanpos, nextpos - 1)
if #substr > 0 and nested_depth == 0 then table.insert(result, substr) end
end
-- Move the scanning position up to just after the character we've just
-- found and handled
scanpos = nextpos + 1
end
-- Handle any trailing bits
local str_trailing = str:sub(scanpos)
if #str_trailing > 0 then table.insert(result, str_trailing) end
return true, result
end
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--- Recombines a list of tokens into a list of commands.
-- @param parts string[] The tokens from tokenise(str).
-- @returns string[] The tokens, but run through trim() & grouped into commands (1 element in the list = 1 command)
local function recombine(parts)
local result = {}
local acc = {}
for i, value in ipairs(parts) do
value = worldeditadditions.trim(value)
if value:sub(1, 1) == "/" and #acc > 0 then
table.insert(result, table.concat(acc, " "))
acc = {}
end
table.insert(acc, value)
end
if #acc > 0 then table.insert(result, table.concat(acc, " ")) end
return result
end
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--- Tokenises a string of multiple commands into an array of individual commands.
-- Preserves the forward slash at the beginning of each command name.
-- Also supports arbitrarily nested and complex curly braces { } for grouping
-- commands together that would normally be split apart.
--
-- Simple example:
-- INPUT: //1 //2 //outset 25 //fixlight
-- OUTPUT: { "//1", "//2", "//outset 25", "//fixlight" }
--
-- Example with curly braces:
-- INPUT: //1 //2 //outset 50 {//many 5 //multi //fixlight //clearcut}
-- OUTPUT: { "//1", "//2", "//outset 50", "//many 5 //multi //fixlight //clearcut"}
--
-- @param command_str str The command string to operate on.
-- @returns bool,(string[]|string) If the operation was successful, then true followed by a table of strings is returned. If the operation was not successful, then false followed by an error message (as a single string) is returned instead.
function worldeditadditions.parse.tokenise_commands(command_str)
local success, result = tokenise(command_str)
if not success then return success, result end
return true, recombine(result)
end
----- Test harness code -----
-----------------------------
-- local function printparts(tbl)
-- for key,value in ipairs(tbl) do
-- print(key..": "..value)
-- end
-- end
--
-- local function test_input(input)
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-- local success, result = worldeditadditions.parse.tokenise_commands(input)
-- if success then
-- printparts(result)
--
-- -- print("RECOMBINED:")
-- -- printparts(recombine(result))
-- else
-- print(result)
-- end
--
-- end
--
-- print("\n\n\n*** 1 ***")
-- test_input("//multi //1 //cubeapply 10 set dirt")
-- print("\n\n\n*** 2 ***")
-- test_input("//multi //1 //2 //outset 50 {//many 5 //multi //fixlight //clearcut}")
-- print("\n\n\n*** 3 ***")
-- test_input("//multi //1 //2 //outset 50 {//many 5 //multi //ellipsoid 10 5 7 glass //clearcut}")
-- print("\n\n\n*** 4 ***")
-- test_input("//multi //1 //2 //outset 50 {//many 5 //multi //ellipsoid 10 5 7 glass //clearcut //many {//set dirt //fixlight}}")
-- print("\n\n\n*** 5 ***")
-- test_input("a { b c d { e f { g h i }j} k l m n}o p")
-- print("\n\n\n*** 6 ***")
-- test_input("a { b c d } e f {{ g h i }j k l m n}o p")