Commit | Line | Data |
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f6146aef JM |
1 | $ErrorActionPreference = "Stop" |
2 | ||
3 | Import-Module $PSScriptRoot/types.psm1 | |
4 | Import-Module $PSScriptRoot/reader.psm1 | |
5 | Import-Module $PSScriptRoot/printer.psm1 | |
6 | Import-Module $PSScriptRoot/env.psm1 | |
7 | Import-Module $PSScriptRoot/core.psm1 | |
8 | ||
9 | # READ | |
10 | function READ([String] $str) { | |
11 | return read_str($str) | |
12 | } | |
13 | ||
14 | # EVAL | |
15 | function pair?($ast) { | |
16 | (sequential? $ast) -and $ast.values.Count -gt 0 | |
17 | } | |
18 | ||
19 | function quasiquote($ast) { | |
20 | if (-not (pair? $ast)) { | |
21 | return (new-list @((new-symbol "quote"), $ast)) | |
22 | } else { | |
23 | $a0 = $ast.nth(0) | |
24 | if ((symbol? $a0) -and $a0.value -ceq "unquote") { | |
25 | return $ast.nth(1) | |
26 | } elseif (pair? $a0) { | |
27 | $a00 = $a0.nth(0) | |
28 | if ((symbol? $a00) -and $a00.value -ceq "splice-unquote") { | |
29 | return (new-list @((new-symbol "concat"), | |
30 | $a0.nth(1), | |
31 | (quasiquote $ast.rest()))) | |
32 | } | |
33 | } | |
34 | return (new-list @((new-symbol "cons"), | |
35 | (quasiquote $a0), | |
36 | (quasiquote $ast.rest()))) | |
37 | } | |
38 | } | |
39 | ||
40 | function macro?($ast, $env) { | |
41 | return (list? $ast) -and | |
42 | (symbol? $ast.nth(0)) -and | |
43 | $env.find($ast.nth(0)) -and | |
44 | $env.get($ast.nth(0)).macro | |
45 | } | |
46 | ||
47 | function macroexpand($ast, $env) { | |
48 | while (macro? $ast $env) { | |
49 | $mac = $env.get($ast.nth(0)).fn | |
50 | $margs = $ast.rest().values | |
51 | $ast = &$mac @margs | |
52 | } | |
53 | return $ast | |
54 | } | |
55 | ||
56 | function eval_ast($ast, $env) { | |
57 | if ($ast -eq $null) { return $ast } | |
58 | switch ($ast.GetType().Name) { | |
59 | "Symbol" { return $env.get($ast) } | |
60 | "List" { return new-list ($ast.values | ForEach { EVAL $_ $env }) } | |
61 | "Vector" { return new-vector ($ast.values | ForEach { EVAL $_ $env }) } | |
62 | "HashMap" { | |
63 | $hm = new-hashmap @() | |
64 | foreach ($k in $ast.values.Keys) { | |
65 | $hm.values[$k] = EVAL $ast.values[$k] $env | |
66 | } | |
67 | return $hm | |
68 | } | |
69 | default { return $ast } | |
70 | } | |
71 | } | |
72 | ||
73 | function EVAL($ast, $env) { | |
74 | while ($true) { | |
75 | #Write-Host "EVAL $(pr_str $ast)" | |
76 | if (-not (list? $ast)) { | |
77 | return (eval_ast $ast $env) | |
78 | } | |
79 | ||
80 | $ast = (macroexpand $ast $env) | |
81 | if (-not (list? $ast)) { | |
82 | return (eval_ast $ast $env) | |
83 | } | |
84 | if (empty? $ast) { return $ast } | |
85 | ||
86 | $a0, $a1, $a2 = $ast.nth(0), $ast.nth(1), $ast.nth(2) | |
87 | switch -casesensitive ($a0.value) { | |
88 | "def!" { | |
89 | return $env.set($a1, (EVAL $a2 $env)) | |
90 | } | |
91 | "let*" { | |
92 | $let_env = new-env $env | |
93 | for ($i=0; $i -lt $a1.values.Count; $i+=2) { | |
94 | $_ = $let_env.set($a1.nth($i), (EVAL $a1.nth(($i+1)) $let_env)) | |
95 | } | |
96 | $env = $let_env | |
97 | $ast = $a2 # TCO | |
98 | } | |
99 | "quote" { | |
100 | return $a1 | |
101 | } | |
102 | "quasiquote" { | |
103 | $ast = quasiquote $a1 | |
104 | } | |
105 | "defmacro!" { | |
106 | $m = EVAL $a2 $env | |
107 | $m.macro = $true | |
108 | return $env.set($a1, $m) | |
109 | } | |
110 | "macroexpand" { | |
111 | return (macroexpand $a1 $env) | |
112 | } | |
113 | "try*" { | |
114 | try { | |
115 | return EVAL $a1 $env | |
116 | } catch { | |
117 | if ($a2 -and ($a2.nth(0).value -ceq "catch*")) { | |
118 | if ($_.Exception.GetType().Name -eq "MalException") { | |
119 | $e = @($_.Exception.object) | |
120 | } else { | |
121 | $e = @($_.Exception.Message) | |
122 | } | |
123 | return (EVAL $a2.nth(2) (new-env $env @($a2.nth(1)) $e)) | |
124 | } else { | |
125 | throw | |
126 | } | |
127 | } | |
128 | } | |
129 | "do" { | |
130 | if ($ast.values.Count -gt 2) { | |
131 | $middle = new-list $ast.values[1..($ast.values.Count-2)] | |
132 | $_ = eval_ast $middle $env | |
133 | } | |
134 | $ast = $ast.last() # TCO | |
135 | } | |
136 | "if" { | |
137 | $cond = (EVAL $a1 $env) | |
138 | if ($cond -eq $null -or | |
139 | ($cond -is [Boolean] -and $cond -eq $false)) { | |
140 | $ast = $ast.nth(3) # TCO | |
141 | } else { | |
142 | $ast = $a2 # TCO | |
143 | } | |
144 | } | |
145 | "fn*" { | |
146 | # Save EVAL into a variable that will get closed over | |
147 | $feval = Get-Command EVAL | |
148 | $fn = { | |
149 | return (&$feval $a2 (new-env $env $a1.values $args)) | |
150 | }.GetNewClosure() | |
151 | return new-malfunc $a2 $a1.values $env $fn | |
152 | } | |
153 | default { | |
154 | $el = (eval_ast $ast $env) | |
155 | $f, $fargs = $el.first(), $el.rest().values | |
156 | if (malfunc? $f) { | |
157 | $env = (new-env $f.env $f.params $fargs) | |
158 | $ast = $f.ast # TCO | |
159 | } else { | |
160 | return &$f @fargs | |
161 | } | |
162 | } | |
163 | } | |
164 | } | |
165 | } | |
166 | ||
167 | ||
168 | function PRINT($exp) { | |
169 | return pr_str $exp $true | |
170 | } | |
171 | ||
172 | # REPL | |
173 | $repl_env = new-env | |
174 | ||
175 | function REP([String] $str) { | |
176 | return PRINT (EVAL (READ $str) $repl_env) | |
177 | } | |
178 | ||
179 | # core.EXT: defined using PowerShell | |
180 | foreach ($kv in $core_ns.GetEnumerator()) { | |
181 | $_ = $repl_env.set((new-symbol $kv.Key), $kv.Value) | |
182 | } | |
183 | $_ = $repl_env.set((new-symbol "eval"), { param($a); (EVAL $a $repl_env) }) | |
184 | $_ = $repl_env.set((new-symbol "*ARGV*"), (new-list $args[1..$args.Count])) | |
185 | ||
186 | # core.mal: defined using the language itself | |
187 | $_ = REP('(def! *host-language* "powershell")') | |
188 | $_ = REP('(def! not (fn* (a) (if a false true)))') | |
189 | $_ = REP('(def! load-file (fn* (f) (eval (read-string (str "(do " (slurp f) ")")))))') | |
190 | $_ = REP("(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw `"odd number of forms to cond`")) (cons 'cond (rest (rest xs)))))))") | |
191 | $_ = REP('(def! *gensym-counter* (atom 0))') | |
192 | $_ = REP('(def! gensym (fn* [] (symbol (str "G__" (swap! *gensym-counter* (fn* [x] (+ 1 x)))))))') | |
193 | $_ = REP('(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) (let* (condvar (gensym)) `(let* (~condvar ~(first xs)) (if ~condvar ~condvar (or ~@(rest xs)))))))))') | |
194 | ||
195 | ||
196 | if ($args.Count -gt 0) { | |
197 | $_ = REP('(load-file "' + $args[0] + '")') | |
198 | exit 0 | |
199 | } | |
200 | ||
201 | $_ = REP('(println (str "Mal [" *host-language* "]"))') | |
202 | while ($true) { | |
203 | Write-Host "user> " -NoNewline | |
204 | $line = [Console]::ReadLine() | |
205 | if ($line -eq $null) { | |
206 | break | |
207 | } | |
208 | try { | |
209 | Write-Host (REP($line)) | |
210 | } catch { | |
211 | if ($_.Exception.GetType().Name -eq "MalException") { | |
212 | Write-Host "Exception: $(pr_str $_.Exception.object)" | |
213 | } else { | |
214 | Write-Host "Exception: $($_.Exception.Message)" | |
215 | } | |
216 | } | |
217 | } |