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See issue #587. * Merge eval-ast and eval into a single conditional. * Expand macros during the apply phase, removing lots of duplicate tests, and increasing the overall consistency by allowing the macro to be computed instead of referenced by name (`((defmacro! cond (...)))` is currently illegal for example). * Print "EVAL: $ast" at the top of EVAL if DEBUG-EVAL exists in the MAL environment. * Remove macroexpand and quasiquoteexpand special forms. * Use pattern-matching style in process/step*.txt. Unresolved issues: c.2: unable to reproduce with gcc 11.12.0. elm: the directory is unchanged. groovy: sometimes fail, but not on each rebuild. nasm: fails some new soft tests, but the issue is unreproducible when running the interpreter manually. objpascal: unreproducible with fpc 3.2.2. ocaml: unreproducible with 4.11.1. perl6: unreproducible with rakudo 2021.09. Unrelated changes: Reduce diff betweens steps. Prevent defmacro! from mutating functions: c forth logo miniMAL vb. dart: fix recent errors and warnings ocaml: remove metadata from symbols. Improve the logo implementation. Encapsulate all representation in types.lg and env.lg, unwrap numbers. Replace some manual iterations with logo control structures. Reduce the diff between steps. Use native iteration in env_get and env_map Rewrite the reader with less temporary strings. Reduce the number of temporary lists (for example, reverse iteration with butlast requires O(n^2) allocations). It seems possible to remove a few exceptions: GC settings (Dockerfile), NO_SELF_HOSTING (IMPLS.yml) and step5_EXCLUDES (Makefile.impls) .
99 lines
2.5 KiB
Dart
99 lines
2.5 KiB
Dart
import 'dart:io';
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import 'printer.dart' as printer;
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import 'reader.dart' as reader;
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import 'types.dart';
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final Map<String, MalType> replEnv = <String, MalType>{
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'+': new MalBuiltin((List<MalType> args) {
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var a = args[0] as MalInt;
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var b = args[1] as MalInt;
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return new MalInt(a.value + b.value);
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}),
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'-': new MalBuiltin((List<MalType> args) {
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var a = args[0] as MalInt;
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var b = args[1] as MalInt;
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return new MalInt(a.value - b.value);
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}),
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'*': new MalBuiltin((List<MalType> args) {
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var a = args[0] as MalInt;
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var b = args[1] as MalInt;
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return new MalInt(a.value * b.value);
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}),
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'/': new MalBuiltin((List<MalType> args) {
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var a = args[0] as MalInt;
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var b = args[1] as MalInt;
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return new MalInt(a.value ~/ b.value);
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})
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};
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MalType READ(String x) => reader.read_str(x);
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class NotFoundException implements Exception {
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/// The name of the symbol that was not found.
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final String value;
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NotFoundException(this.value);
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}
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MalType EVAL(MalType ast, Map<String, MalType> env) {
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// stdout.writeln("EVAL: ${printer.pr_str(ast)}");
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if (ast is MalSymbol) {
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var result = env[ast.value];
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if (result == null) {
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throw new NotFoundException(ast.value);
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}
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return result;
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} else if (ast is MalList) {
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// Exit this switch.
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} else if (ast is MalVector) {
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return new MalVector(ast.elements.map((x) => EVAL(x, env)).toList());
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} else if (ast is MalHashMap) {
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var newMap = new Map<MalType, MalType>.from(ast.value);
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for (var key in newMap.keys) {
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newMap[key] = EVAL(newMap[key], env);
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}
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return new MalHashMap(newMap);
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} else {
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return ast;
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}
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// ast is a list. todo: indent left.
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var forms = (ast as MalList).elements;
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if (forms.isEmpty) {
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return ast;
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} else {
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MalBuiltin f = EVAL(forms.first, env);
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List<MalType> args = forms.sublist(1).map((x) => EVAL(x, env)).toList();
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return f.call(args);
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}
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}
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String PRINT(MalType x) => printer.pr_str(x);
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String rep(String x) {
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return PRINT(EVAL(READ(x), replEnv));
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}
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const prompt = 'user> ';
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main() {
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while (true) {
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stdout.write(prompt);
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var input = stdin.readLineSync();
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if (input == null) return;
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var output;
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try {
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output = rep(input);
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} on reader.ParseException catch (e) {
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stdout.writeln("Error: '${e.message}'");
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continue;
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} on NotFoundException catch (e) {
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stdout.writeln("Error: '${e.value}' not found");
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continue;
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} on reader.NoInputException {
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continue;
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}
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stdout.writeln(output);
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}
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}
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