2019-09-18 21:04:02 +03:00
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import "./env" for Env
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import "./readline" for Readline
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import "./reader" for MalReader
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import "./printer" for Printer
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import "./types" for MalSymbol, MalList, MalVector, MalMap, MalNativeFn, MalFn
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import "./core" for Core
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class Mal {
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static read(str) {
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return MalReader.read_str(str)
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}
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2022-01-10 02:15:40 +03:00
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static eval(ast, env) {
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while (true) {
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var tco = false
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var dbgenv = env.find("DEBUG-EVAL")
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if (dbgenv && env.get("DEBUG-EVAL")) {
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System.print("EVAL: %(print(ast))")
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}
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// Process non-list types.
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2019-09-18 21:04:02 +03:00
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if (ast is MalSymbol) {
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return env.get(ast.value)
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} else if (ast is MalList) {
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2022-01-10 02:15:40 +03:00
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// The only case leading after this switch.
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2019-09-18 21:04:02 +03:00
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} else if (ast is MalVector) {
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return MalVector.new(ast.elements.map { |e| eval(e, env) }.toList)
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} else if (ast is MalMap) {
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var m = {}
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for (e in ast.data) {
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m[e.key] = eval(e.value, env)
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}
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return MalMap.new(m)
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} else {
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return ast
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}
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2022-01-10 02:15:40 +03:00
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// ast is a list, search for special forms
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2019-09-18 21:04:02 +03:00
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if (ast.isEmpty) return ast
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if (ast[0] is MalSymbol) {
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if (ast[0].value == "def!") {
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return env.set(ast[1].value, eval(ast[2], env))
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} else if (ast[0].value == "let*") {
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var letEnv = Env.new(env)
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var i = 0
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while (i < ast[1].count) {
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letEnv.set(ast[1][i].value, eval(ast[1][i + 1], letEnv))
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i = i + 2
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}
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ast = ast[2]
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env = letEnv
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tco = true
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} else if (ast[0].value == "do") {
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for (i in 1...(ast.count - 1)) {
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eval(ast[i], env)
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}
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ast = ast[-1]
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tco = true
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} else if (ast[0].value == "if") {
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var condval = eval(ast[1], env)
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if (condval) {
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ast = ast[2]
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} else {
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if (ast.count <= 3) return null
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ast = ast[3]
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}
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tco = true
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} else if (ast[0].value == "fn*") {
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return MalFn.new(ast[2], ast[1].elements, env,
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Fn.new { |a| eval(ast[2], Env.new(env, ast[1].elements, a)) })
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}
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}
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if (!tco) {
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2022-01-10 02:15:40 +03:00
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var evaled_ast = ast.elements.map { |e| eval(e, env) }.toList
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2019-09-18 21:04:02 +03:00
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var f = evaled_ast[0]
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if (f is MalNativeFn) {
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return f.call(evaled_ast[1..-1])
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} else if (f is MalFn) {
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ast = f.ast
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env = Env.new(f.env, f.params, evaled_ast[1..-1])
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tco = true
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} else {
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Fiber.abort("unknown function type")
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}
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}
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}
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}
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static print(ast) {
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return Printer.pr_str(ast)
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}
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static rep(str) {
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return print(eval(read(str), __repl_env))
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}
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static main() {
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__repl_env = Env.new()
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// core.wren: defined in wren
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for (e in Core.ns) { __repl_env.set(e.key, e.value) }
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// core.mal: defined using the language itself
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rep("(def! not (fn* (a) (if a false true)))")
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while (true) {
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var line = Readline.readLine("user> ")
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if (line == null) break
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if (line != "") {
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var fiber = Fiber.new { System.print(rep(line)) }
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fiber.try()
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if (fiber.error) System.print("Error: %(fiber.error)")
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}
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}
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System.print()
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}
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}
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Mal.main()
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