Blame: impls/lua/step2_eval.lua - kanaka/mal

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mal - Make a Lisp

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Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`#!/usr/bin/env lua`

			`local table = require('table')`

			`local readline = require('readline')`
			`local utils = require('utils')`
			`local types = require('types')`
			`local reader = require('reader')`
			`local printer = require('printer')`
			`local List, Vector, HashMap = types.List, types.Vector, types.HashMap`

			`-- read`
			`function READ(str)`
			`return reader.read_str(str)`
			`end`

			`-- eval`
lua: merge eval and eval AST 2024-08-22 01:51:28 +02:00
			`function EVAL(ast, env)`

			`-- print("EVAL: " .. printer._pr_str(ast, true))`

Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`if types._symbol_Q(ast) then`
			`if env[ast.val] == nil then`
			`types.throw("'"..ast.val.."' not found")`
			`end`
			`return env[ast.val]`
			`elseif types._vector_Q(ast) then`
			`return Vector:new(utils.map(function(x) return EVAL(x,env) end,ast))`
			`elseif types._hash_map_Q(ast) then`
			`local new_hm = {}`
			`for k,v in pairs(ast) do`
Stop evaluating map keys Neither keywords nor strings are modified by evaluation, so evaluating map keys is a no-op. Document this in the guide. 2021-08-21 19:08:17 +02:00			`new_hm[k] = EVAL(v, env)`
Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`end`
			`return HashMap:new(new_hm)`
lua: merge eval and eval AST 2024-08-22 01:51:28 +02:00			`elseif not types._list_Q(ast) or #ast == 0 then`
Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`return ast`
			`end`

lua: merge eval and eval AST 2024-08-22 01:51:28 +02:00			`local f = EVAL(ast[1], env)`
			`local args = types.slice(ast, 2)`
			`args = utils.map(function(x) return EVAL(x,env) end, args)`
lua: update to version 5.2 - Update to support the new behavior of varargs and table.pack/unpack in lua 5.2 - Bump up the stack overflow test since lua 5.2 seems to support much larger stacks before overflow. - Fix a latent issue in if forms where false in the 4th position would result in nil returned. Add a new test to catch this in the future. 2019-01-28 13:31:28 -06:00			`return f(table.unpack(args))`
Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`end`

			`-- print`
			`function PRINT(exp)`
			`return printer._pr_str(exp, true)`
			`end`

			`-- repl`
			`local repl_env = {['+'] = function(a,b) return a+b end,`
			`['-'] = function(a,b) return a-b end,`
			`[''] = function(a,b) return ab end,`
			`['/'] = function(a,b) return math.floor(a/b) end}`
			`function rep(str)`
			`return PRINT(EVAL(READ(str),repl_env))`
			`end`

Lua: fix with new runtest.py 2015-02-28 15:58:35 -06:00			`if #arg > 0 and arg[1] == "--raw" then`
			`readline.raw = true`
			`end`

Lua: all steps and self-hosting. Also some misc docs/TODO updates. 2015-01-08 23:25:40 -06:00			`while true do`
			`line = readline.readline("user> ")`
			`if not line then break end`
			`xpcall(function()`
			`print(rep(line))`
			`end, function(exc)`
			`if exc then`
			`if types._malexception_Q(exc) then`
			`exc = printer._pr_str(exc.val, true)`
			`end`
			`print("Error: " .. exc)`
			`print(debug.traceback())`
			`end`
			`end)`
			`end`