Artifact bcefce47daacc4a5e6725cb32d499b73e6f1ac11
1 /**
2 * Authors: k.inaba
3 * License: NYSL 0.9982 http://www.kmonos.net/nysl/
4 *
5 * Evaluator for Polemy programming language.
6 */
7 module polemy.eval;
8 import polemy._common;
9 import polemy.lex : LexPosition;
10 import polemy.ast;
11 import polemy.parse;
12 import polemy.value;
13 import std.typecons;
14 import std.stdio;
15
16 Context createGlobalContext()
17 {
18 auto ctx = new Context;
19 ctx.add("+", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
20 if( args.length != 2 )
21 throw new PolemyRuntimeException("+ takes two arguments!! ["~to!string(pos)~"]");
22 if( auto x = cast(IntValue)args[0] )
23 if( auto y = cast(IntValue)args[1] )
24 return new IntValue(x.data+y.data);
25 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
26 }));
27 ctx.add("-", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
28 if( args.length != 2 )
29 throw new PolemyRuntimeException("- takes two arguments!! ["~to!string(pos)~"]");
30 if( auto x = cast(IntValue)args[0] )
31 if( auto y = cast(IntValue)args[1] )
32 return new IntValue(x.data-y.data);
33 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
34 }));
35 ctx.add("*", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
36 if( args.length != 2 )
37 throw new PolemyRuntimeException("* takes two arguments!! ["~to!string(pos)~"]");
38 if( auto x = cast(IntValue)args[0] )
39 if( auto y = cast(IntValue)args[1] )
40 return new IntValue(x.data*y.data);
41 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
42 }));
43 ctx.add("/", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
44 if( args.length != 2 )
45 throw new PolemyRuntimeException("/ takes two arguments!! ["~to!string(pos)~"]");
46 if( auto x = cast(IntValue)args[0] )
47 if( auto y = cast(IntValue)args[1] )
48 return new IntValue(x.data/y.data);
49 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
50 }));
51 ctx.add("<", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
52 if( args.length != 2 )
53 throw new PolemyRuntimeException("< takes two arguments!! ["~to!string(pos)~"]");
54 if( auto x = cast(IntValue)args[0] )
55 if( auto y = cast(IntValue)args[1] )
56 return new IntValue(BigInt(to!int(x.data < y.data)));
57 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
58 }));
59 ctx.add(">", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
60 if( args.length != 2 )
61 throw new PolemyRuntimeException("> takes two arguments!! ["~to!string(pos)~"]");
62 if( auto x = cast(IntValue)args[0] )
63 if( auto y = cast(IntValue)args[1] )
64 return new IntValue(BigInt(to!int(x.data>y.data)));
65 throw new PolemyRuntimeException("cannot add non-integers ["~to!string(pos)~"]");
66 }));
67 ctx.add("print", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
68 foreach(a; args)
69 write(a);
70 writeln("");
71 return new UndefinedValue;
72 }));
73 ctx.add("if", new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
74 if( args.length != 3 )
75 throw new PolemyRuntimeException("if takes three arguments!! ["~to!string(pos)~"]");
76 if( auto x = cast(IntValue)args[0] )
77 if( auto ft = cast(FunValue)args[1] )
78 if( auto fe = cast(FunValue)args[2] )
79 return (x.data == 0 ? fe : ft).call(pos,[]);
80 throw new PolemyRuntimeException("type mismatch in if ["~to!string(pos)~"]");
81 }));
82 return ctx;
83 }
84
85 Tuple!(Value,"val",Context,"ctx") evalString(T...)(T params)
86 {
87 return eval( parserFromString(params).parseProgram() );
88 }
89
90 Tuple!(Value,"val",Context,"ctx") evalFile(T...)(T params)
91 {
92 return eval( parserFromFile(params).parseProgram() );
93 }
94
95 Tuple!(Value,"val",Context,"ctx") eval(Program prog)
96 {
97 Context ctx = createGlobalContext();
98 return typeof(return)(eval(prog, ctx), ctx);
99 }
100
101 Value eval(Program prog, Context ctx)
102 {
103 Value v = new UndefinedValue;
104 foreach(s; prog)
105 v = eval(s, ctx);
106 return v;
107 }
108
109 Value eval(Statement _s, Context ctx)
110 {
111 if( auto s = cast(DeclStatement)_s )
112 {
113 auto v = eval(s.expr, ctx);
114 ctx.add(s.var, v);
115 return v;
116 }
117 else
118 if( auto s = cast(ExprStatement)_s )
119 {
120 return eval(s.expr, ctx);
121 }
122 throw new PolemyRuntimeException(sprintf!"Unknown Kind of Statement %s at [%s]"(typeid(_s), _s.pos));
123 }
124
125 Value eval(Expression _e, Context ctx)
126 {
127 if( auto e = cast(StrLiteralExpression)_e )
128 {
129 return new StrValue(e.data);
130 }
131 else
132 if( auto e = cast(IntLiteralExpression)_e )
133 {
134 return new IntValue(e.data);
135 }
136 else
137 if( auto e = cast(VarExpression)_e )
138 {
139 return ctx[e.var];
140 }
141 else
142 if( auto e = cast(AssignExpression)_e )
143 {
144 if( auto ev = cast(VarExpression)e.lhs )
145 {
146 Value r = eval(e.rhs, ctx);
147 ctx[ev.var] = r;
148 return r;
149 }
150 throw new PolemyRuntimeException(sprintf!"Lhs of assignment must be a variable: %s"(e.pos));
151 }
152 else
153 if( auto e = cast(FuncallExpression)_e )
154 {
155 Value _f = eval(e.fun, ctx);
156 if( auto f = cast(FunValue)_f ) {
157 Value[] args;
158 foreach(a; e.args)
159 args ~= eval(a, ctx);
160 return f.call(e.pos, args);
161 } else
162 throw new PolemyRuntimeException(sprintf!"Non-funcion is applied at [%s]"(e.pos));
163 }
164 else
165 if( auto e = cast(FunLiteralExpression)_e )
166 {
167 return new FunValue(delegate Value(immutable LexPosition pos, Value[] args){
168 if( e.params.length != args.length )
169 throw new PolemyRuntimeException(sprintf!"Argument Number Mismatch (%d required but %d given) at [%s]"
170 (e.params.length, args.length, e.pos));
171 Context ctxNeo = new Context(ctx);
172 foreach(i,p; e.params)
173 ctxNeo.add(p, args[i]);
174 return eval(e.funbody, ctxNeo);
175 });
176 }
177 throw new PolemyRuntimeException(sprintf!"Unknown Kind of Expression %s at [%s]"(typeid(_e), _e.pos));
178 }
179
180 import std.stdio;
181 unittest
182 {
183 auto r = evalString(`var x = 21; x = x + x*x;`);
184 assert( r.val == new IntValue(BigInt(21+21*21)) );
185 assert( r.ctx["x"] == new IntValue(BigInt(21+21*21)) );
186 assert( !collectException(r.ctx["x"]) );
187 assert( collectException(r.ctx["y"]) );
188 }
189 unittest
190 {
191 assert( collectException(evalString(`var x = 21; x = x + x*y;`)) );
192 assert( collectException(evalString(`x=1;`)) );
193 }
194 unittest
195 {
196 auto r = evalString(`var x = fun(a){1+a;}(2);`);
197 assert( r.ctx["x"] == new IntValue(BigInt(3)) );
198 assert( r.val == new IntValue(BigInt(3)) );
199 }
200 unittest
201 {
202 auto r = evalString(`var x = 1; var f = fun(){x=x+1;}; f(); f(); f();`);
203 assert( r.ctx["x"] == new IntValue(BigInt(4)) );
204 assert( r.val == new IntValue(BigInt(4)) );
205 }
206 unittest
207 {
208 evalString(`print("Hello, world!");`);
209 evalString(`print(fun(){});`);
210 }
211 unittest
212 {
213 evalString(`var fac = fun(x){
214 1;
215 };
216 print(fac(3));`);
217 evalString(`var fac = fun(x){
218 if(x)
219 { x*fac(x-1); }
220 else
221 { 1; };
222 };
223 print(fac(10));`);
224 evalString(`var fib = fun(x){
225 if(x<2)
226 { 1; }
227 else
228 { fib(x-1) + fib(x-2); };
229 };
230 print(fib(10));`);
231 }