1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
/*****
* env.h
* Andy Hammerlindl 2002/6/20
*
* Keeps track of the namespaces of variables and types when traversing
* the abstract syntax.
*****/
#ifndef ENV_H
#define ENV_H
#include "errormsg.h"
#include "entry.h"
#include "types.h"
#include "util.h"
namespace types {
class record;
}
namespace absyntax {
class namedTyEntry;
}
namespace trans {
using sym::symbol;
using types::ty;
using types::function;
using types::record;
class genv;
// Keeps track of the name bindings of variables and types. This is used for
// the fields of a record, whereas the derived class env is used for
// unqualified names in translation.
class protoenv {
//protected:
public:
// These tables keep track of type and variable definitions.
tenv te;
venv ve;
access *baseLookupCast(ty *target, ty *source, symbol name);
public:
// Start an environment for a file-level module.
protoenv() {}
protoenv(venv::file_env_tag tag)
: ve(tag) {}
protoenv(const protoenv&);
void beginScope()
{
te.beginScope(); ve.beginScope();
}
void endScope()
{
te.endScope(); ve.endScope();
}
void collapseScope()
{
te.collapseScope(); ve.collapseScope();
}
tyEntry *lookupTyEntry(symbol s)
{
return te.look(s);
}
ty *lookupType(symbol s)
{
tyEntry *ent=lookupTyEntry(s);
return ent ? ent->t : 0;
}
varEntry *lookupVarByType(symbol name, ty *t)
{
// Search in local vars.
return ve.lookByType(name, t);
}
varEntry *lookupVarBySignature(symbol name, types::signature *sig)
{
return ve.lookBySignature(name, sig);
}
access *lookupInitializer(ty *t)
{
// The initializer's type is a function returning the desired type.
function *it=new function(t);
varEntry *v=lookupVarByType(symbol::initsym,it);
// If not in the environment, try the type itself.
return v ? v->getLocation() : t->initializer();
}
// Find the function that handles casting between the types.
// The name is "operator cast" for implicit casting and "operator ecast" for
// explicit.
access *lookupCast(ty *target, ty *source, symbol name);
bool castable(ty *target, ty *source, symbol name);
// A cast lookup designed to work quickly with the application matching
// code. The target type must not be overloaded.
bool fastCastable(ty *target, ty *source);
// For the lookup, neither target nor source may be overloaded.
access *fastLookupCast(ty *target, ty *source);
// Given overloaded types, this resolves which types should be the target and
// the source of the cast.
ty *castTarget(ty *target, ty *source, symbol name);
ty *castSource(ty *target, ty *source, symbol name);
ty *varGetType(symbol name)
{
return ve.getType(name);
}
void addType(symbol name, tyEntry *desc)
{
te.enter(name, desc);
}
void addVar(symbol name, varEntry *desc)
{
// Don't check for multiple variables, as this makes adding casts
// and initializers harder.
ve.enter(name, desc);
}
// Add another environment, say from a record.
void add(protoenv &source, varEntry *qualifier, coder &c)
{
te.add(source.te, qualifier, c);
ve.add(source.ve, qualifier, c);
}
// Add variables and types of name src from another environment under the
// name dest in this environment.
bool add(symbol src, symbol dest,
protoenv &source, varEntry *qualifier, coder &c)
{
bool teAdd=te.add(src, dest, source.te, qualifier, c);
bool veAdd=ve.add(src, dest, source.ve, qualifier, c);
return teAdd || veAdd;
}
// Add the standard functions for a new type.
void addArrayOps(types::array *t);
void addRecordOps(types::record *r);
void addFunctionOps(types::function *f);
void list(record *r=0)
{
ve.list(r);
}
// Adds to a list the keywords in the environment that start with the given
// prefix. Used for automatic completion at the interactive prompt.
typedef mem::list<symbol> symbol_list;
void completions(symbol_list &l, string start)
{
te.completions(l, start);
ve.completions(l, start);
}
private: // Non-copyable
void operator=(const protoenv&);
};
// Environment used in translating statements and expressions at all scopes. As
// opposed to protoenv which is suitable for keeping track of the fields of
// records, this also keeps track of the global env, for loading modules.
class env : public protoenv {
// The global environment - keeps track of modules.
genv ≥
public:
// Start an environment for a file-level module.
env(genv &ge);
~env();
record *getModule(symbol id, string filename);
record *getTemplatedModule(symbol id,
string filename,
string index,
mem::vector<absyntax::namedTyEntry*> *args,
trans::frame *parent
);
};
} // namespace trans
#endif
|
