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ee7cd585 JM |
1 | Imports System |
2 | Imports System.IO | |
3 | Imports System.Collections.Generic | |
4 | Imports Mal | |
5 | Imports MalVal = Mal.types.MalVal | |
6 | Imports MalInt = Mal.types.MalInt | |
7 | Imports MalSymbol = Mal.types.MalSymbol | |
8 | Imports MalList = Mal.types.MalList | |
9 | Imports MalVector = Mal.types.MalVector | |
10 | Imports MalHashMap = Mal.types.MalHashMap | |
11 | Imports MalFunc = Mal.types.MalFunc | |
12 | Imports MalEnv = Mal.env.Env | |
13 | ||
14 | Namespace Mal | |
aaba2493 | 15 | Class step5_tco |
ee7cd585 JM |
16 | ' read |
17 | Shared Function READ(str As String) As MalVal | |
18 | Return reader.read_str(str) | |
19 | End Function | |
20 | ||
21 | ' eval | |
22 | Shared Function eval_ast(ast As MalVal, env As MalEnv) As MalVal | |
23 | If TypeOf ast Is MalSymbol Then | |
24 | Dim sym As MalSymbol = DirectCast(ast, MalSymbol) | |
25 | return env.do_get(sym.getName()) | |
26 | Else If TypeOf ast Is MalList Then | |
27 | Dim old_lst As MalList = DirectCast(ast, MalList) | |
28 | Dim new_lst As MalList | |
29 | If ast.list_Q() Then | |
30 | new_lst = New MalList | |
31 | Else | |
32 | new_lst = DirectCast(New MalVector, MalList) | |
33 | End If | |
34 | Dim mv As MalVal | |
35 | For Each mv in old_lst.getValue() | |
36 | new_lst.conj_BANG(EVAL(mv, env)) | |
37 | Next | |
38 | return new_lst | |
39 | Else If TypeOf ast Is MalHashMap Then | |
40 | Dim new_dict As New Dictionary(Of String, MalVal) | |
41 | Dim entry As KeyValuePair(Of String, MalVal) | |
42 | For Each entry in DirectCast(ast,MalHashMap).getValue() | |
43 | new_dict.Add(entry.Key, EVAL(DirectCast(entry.Value,MalVal), env)) | |
44 | Next | |
45 | return New MalHashMap(new_dict) | |
46 | Else | |
47 | return ast | |
48 | End If | |
49 | return ast | |
50 | End Function | |
51 | ||
52 | ' TODO: move to types.vb when it is ported | |
53 | Class FClosure | |
54 | Public ast As MalVal | |
55 | Public params As MalList | |
56 | Public env As MalEnv | |
57 | Function fn(args as MalList) As MalVal | |
58 | return EVAL(ast, new MalEnv(env, params, args)) | |
59 | End Function | |
60 | End Class | |
61 | ||
62 | Shared Function EVAL(orig_ast As MalVal, env As MalEnv) As MalVal | |
63 | Do | |
64 | ||
65 | 'Console.WriteLine("EVAL: {0}", printer._pr_str(orig_ast, true)) | |
66 | If not orig_ast.list_Q() Then | |
67 | return eval_ast(orig_ast, env) | |
68 | End If | |
69 | ||
70 | ' apply list | |
71 | Dim ast As MalList = DirectCast(orig_ast, MalList) | |
72 | If ast.size() = 0 Then | |
73 | return ast | |
74 | End If | |
75 | Dim a0 As MalVal = ast(0) | |
76 | Dim a0sym As String | |
77 | If TypeOf a0 is MalSymbol Then | |
78 | a0sym = DirectCast(a0,MalSymbol).getName() | |
79 | Else | |
80 | a0sym = "__<*fn*>__" | |
81 | End If | |
82 | ||
83 | Select a0sym | |
84 | Case "def!" | |
85 | Dim a1 As MalVal = ast(1) | |
86 | Dim a2 As MalVal = ast(2) | |
87 | Dim res As MalVal = EVAL(a2, env) | |
88 | env.do_set(DirectCast(a1,MalSymbol).getName(), res) | |
89 | return res | |
90 | Case "let*" | |
91 | Dim a1 As MalVal = ast(1) | |
92 | Dim a2 As MalVal = ast(2) | |
93 | Dim key As MalSymbol | |
94 | Dim val as MalVal | |
95 | Dim let_env As new MalEnv(env) | |
96 | For i As Integer = 0 To (DirectCast(a1,MalList)).size()-1 Step 2 | |
97 | key = DirectCast(DirectCast(a1,MalList)(i),MalSymbol) | |
98 | val = DirectCast(a1,MalList)(i+1) | |
99 | let_env.do_set(key.getName(), EVAL(val, let_env)) | |
100 | Next | |
101 | orig_ast = a2 | |
102 | env = let_env | |
103 | Case "do" | |
104 | eval_ast(ast.slice(1, ast.size()-1), env) | |
105 | orig_ast = ast(ast.size()-1) | |
106 | Case "if" | |
107 | Dim a1 As MalVal = ast(1) | |
108 | Dim cond As MalVal = EVAL(a1, env) | |
109 | If cond Is Mal.types.Nil or cond Is Mal.types.MalFalse Then | |
110 | ' eval false slot form | |
111 | If ast.size() > 3 Then | |
112 | orig_ast = ast(3) | |
113 | Else | |
114 | return Mal.types.Nil | |
115 | End If | |
116 | Else | |
117 | ' eval true slot form | |
118 | orig_ast = ast(2) | |
119 | ||
120 | End If | |
121 | Case "fn*" | |
122 | Dim fc As New FClosure() | |
123 | fc.ast = ast(2) | |
124 | fc.params = DirectCast(ast(1),MalLIst) | |
125 | fc.env = env | |
126 | Dim f As Func(Of MalList, MalVal) = AddressOf fc.fn | |
127 | Dim mf As new MalFunc(ast(2), env, | |
128 | DirectCast(ast(1),MalList), f) | |
129 | return DirectCast(mf,MalVal) | |
130 | Case Else | |
131 | Dim el As MalList = DirectCast(eval_ast(ast, env), MalList) | |
132 | Dim f As MalFunc = DirectCast(el(0), MalFunc) | |
133 | Dim fnast As MalVal = f.getAst() | |
134 | If not fnast Is Nothing | |
135 | orig_ast = fnast | |
136 | env = f.genEnv(el.rest()) | |
137 | Else | |
138 | Return f.apply(el.rest()) | |
139 | End If | |
140 | End Select | |
141 | ||
142 | Loop While True | |
143 | End Function | |
144 | ||
145 | ||
146 | Shared Function PRINT(exp As MalVal) As String | |
147 | return printer._pr_str(exp, TRUE) | |
148 | End Function | |
149 | ||
150 | ' repl | |
151 | Shared repl_env As MalEnv | |
152 | ||
153 | Shared Function REP(str As String) As String | |
154 | Return PRINT(EVAL(READ(str), repl_env)) | |
155 | End Function | |
156 | ||
157 | Shared Function Main As Integer | |
158 | Dim args As String() = Environment.GetCommandLineArgs() | |
159 | ||
160 | repl_env = New MalEnv(Nothing) | |
161 | ||
162 | ' core.vb: defined using VB.NET | |
163 | For Each entry As KeyValuePair(Of String,MalVal) In core.ns() | |
164 | repl_env.do_set(entry.Key, entry.Value) | |
165 | Next | |
166 | ||
167 | ' core.mal: defined using the language itself | |
168 | REP("(def! not (fn* (a) (if a false true)))") | |
169 | ||
170 | If args.Length > 1 AndAlso args(1) = "--raw" Then | |
171 | Mal.readline.SetMode(Mal.readline.Modes.Raw) | |
172 | End If | |
173 | ||
174 | ' repl loop | |
175 | Dim line As String | |
176 | Do | |
177 | Try | |
178 | line = Mal.readline.Readline("user> ") | |
179 | If line is Nothing Then | |
180 | Exit Do | |
181 | End If | |
182 | If line = "" Then | |
183 | Continue Do | |
184 | End If | |
185 | Catch e As IOException | |
186 | Console.WriteLine("IOException: " & e.Message) | |
187 | End Try | |
188 | Try | |
189 | Console.WriteLine(REP(line)) | |
190 | Catch e as Exception | |
191 | Console.WriteLine("Error: " & e.Message) | |
192 | Console.WriteLine(e.StackTrace) | |
193 | Continue Do | |
194 | End Try | |
195 | Loop While True | |
196 | End function | |
aaba2493 | 197 | End Class |
ee7cd585 | 198 | End Namespace |