Commit | Line | Data |
---|---|---|
095b73ea | 1 | #! /usr/bin/env crystal run |
2 | ||
5185c56e | 3 | require "readline" |
095b73ea | 4 | require "./reader" |
5 | require "./printer" | |
6 | require "./types" | |
7 | require "./env" | |
b31653d5 | 8 | require "./core" |
2c76c2ff | 9 | require "./error" |
095b73ea | 10 | |
11 | # Note: | |
12 | # Employed downcase names because Crystal prohibits uppercase names for methods | |
13 | ||
97d0deb1 | 14 | module Mal |
15 | extend self | |
16 | ||
17 | def func_of(env, binds, body) | |
5185c56e | 18 | ->(args : Array(Mal::Type)) { |
97d0deb1 | 19 | new_env = Mal::Env.new(env, binds, args) |
20 | eval(body, new_env) | |
5185c56e | 21 | }.as(Mal::Func) |
97d0deb1 | 22 | end |
095b73ea | 23 | |
97d0deb1 | 24 | def eval_ast(ast, env) |
5185c56e | 25 | return ast.map { |n| eval(n, env).as(Mal::Type) } if ast.is_a? Mal::List |
7fe6282e | 26 | |
97d0deb1 | 27 | val = ast.unwrap |
7fe6282e | 28 | |
97d0deb1 | 29 | Mal::Type.new case val |
30 | when Mal::Symbol | |
31 | if e = env.get(val.str) | |
32 | e | |
33 | else | |
34 | eval_error "'#{val.str}' not found" | |
35 | end | |
36 | when Mal::List | |
5185c56e | 37 | val.each_with_object(Mal::List.new) { |n, l| l << eval(n, env) } |
97d0deb1 | 38 | when Mal::Vector |
5185c56e | 39 | val.each_with_object(Mal::Vector.new) { |n, l| l << eval(n, env) } |
97d0deb1 | 40 | when Mal::HashMap |
5185c56e | 41 | val.each { |k, v| val[k] = eval(v, env) } |
97d0deb1 | 42 | val |
095b73ea | 43 | else |
97d0deb1 | 44 | val |
095b73ea | 45 | end |
095b73ea | 46 | end |
51be5007 | 47 | |
97d0deb1 | 48 | def eval_invocation(list, env) |
49 | f = eval(list.first, env).unwrap | |
50 | eval_error "expected function symbol as the first symbol of list" unless f.is_a? Mal::Func | |
5185c56e | 51 | f.call eval_ast(list[1..-1].each_with_object(Mal::List.new) { |i, l| l << i }, env) |
97d0deb1 | 52 | end |
095b73ea | 53 | |
97d0deb1 | 54 | def read(str) |
55 | read_str str | |
56 | end | |
bed63064 | 57 | |
97d0deb1 | 58 | def eval(ast, env) |
59 | list = ast.unwrap | |
60 | ||
5185c56e | 61 | return eval_ast(ast, env) unless list.is_a? Mal::List |
97d0deb1 | 62 | return gen_type Mal::List if list.empty? |
63 | ||
64 | head = list.first.unwrap | |
65 | ||
66 | Mal::Type.new case head | |
67 | when Mal::Symbol | |
68 | case head.str | |
69 | when "def!" | |
70 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 | |
71 | a1 = list[1].unwrap | |
72 | eval_error "1st argument of 'def!' must be symbol" unless a1.is_a? Mal::Symbol | |
73 | env.set(a1.str, eval(list[2], env)) | |
74 | when "let*" | |
75 | eval_error "wrong number of argument for 'def!'" unless list.size == 3 | |
76 | ||
77 | bindings = list[1].unwrap | |
78 | eval_error "1st argument of 'let*' must be list or vector" unless bindings.is_a? Array | |
79 | eval_error "size of binding list must be even" unless bindings.size.even? | |
80 | ||
81 | new_env = Mal::Env.new env | |
82 | bindings.each_slice(2) do |binding| | |
83 | key, value = binding | |
84 | name = key.unwrap | |
85 | eval_error "name of binding must be specified as symbol" unless name.is_a? Mal::Symbol | |
86 | new_env.set(name.str, eval(value, new_env)) | |
87 | end | |
88 | ||
89 | eval(list[2], new_env) | |
90 | when "do" | |
91 | list.shift 1 | |
92 | eval_ast(list, env).last | |
93 | when "if" | |
94 | cond = eval(list[1], env).unwrap | |
95 | case cond | |
96 | when Nil | |
97 | list.size >= 4 ? eval(list[3], env) : nil | |
98 | when false | |
5185c56e | 99 | list.size >= 4 ? eval(list[3], env) : nil |
97d0deb1 | 100 | else |
101 | eval(list[2], env) | |
102 | end | |
103 | when "fn*" | |
104 | # Note: | |
105 | # If writing lambda expression here directly, compiler will fail to infer type of 'list'. (Error 'Nil for empty?') | |
106 | func_of(env, list[1].unwrap, list[2]) | |
bed63064 | 107 | else |
97d0deb1 | 108 | eval_invocation(list, env) |
bed63064 | 109 | end |
095b73ea | 110 | else |
51be5007 | 111 | eval_invocation(list, env) |
095b73ea | 112 | end |
095b73ea | 113 | end |
095b73ea | 114 | |
97d0deb1 | 115 | def print(result) |
116 | pr_str(result, true) | |
117 | end | |
095b73ea | 118 | |
97d0deb1 | 119 | def rep(str) |
5185c56e | 120 | print(eval(read(str), REPL_ENV)) |
97d0deb1 | 121 | end |
095b73ea | 122 | end |
123 | ||
5185c56e OR |
124 | REPL_ENV = Mal::Env.new nil |
125 | Mal::NS.each { |k, v| REPL_ENV.set(k, Mal::Type.new(v)) } | |
97d0deb1 | 126 | Mal.rep "(def! not (fn* (a) (if a false true)))" |
b31653d5 | 127 | |
5185c56e | 128 | while line = Readline.readline("user> ") |
095b73ea | 129 | begin |
97d0deb1 | 130 | puts Mal.rep(line) |
dd7a4f55 JM |
131 | rescue e : Mal::RuntimeException |
132 | STDERR.puts "Error: #{pr_str(e.thrown, true)}" | |
095b73ea | 133 | rescue e |
dd7a4f55 | 134 | STDERR.puts "Error: #{e}" |
095b73ea | 135 | end |
136 | end |