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
|
/* -*- c++ -*- */
/*
* Copyright © 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#pragma once
#ifndef S_EXPRESSION_H
#define S_EXPRESSION_H
#include "main/core.h" /* for Elements */
#include "util/strtod.h"
#include "list.h"
/* Type-safe downcasting macros (also safe to pass NULL) */
#define SX_AS_(t,x) ((x) && ((s_expression*) x)->is_##t()) ? ((s_##t*) (x)) \
: NULL
#define SX_AS_LIST(x) SX_AS_(list, x)
#define SX_AS_SYMBOL(x) SX_AS_(symbol, x)
#define SX_AS_NUMBER(x) SX_AS_(number, x)
#define SX_AS_INT(x) SX_AS_(int, x)
/* Pattern matching macros */
#define MATCH(list, pat) s_match(list, ARRAY_SIZE(pat), pat, false)
#define PARTIAL_MATCH(list, pat) s_match(list, ARRAY_SIZE(pat), pat, true)
/* For our purposes, S-Expressions are:
* - <int>
* - <float>
* - symbol
* - (expr1 expr2 ... exprN) where exprN is an S-Expression
*
* Unlike LISP/Scheme, we do not support (foo . bar) pairs.
*/
class s_expression : public exec_node
{
public:
/**
* Read an S-Expression from the given string.
* Advances the supplied pointer to just after the expression read.
*
* Any allocation will be performed with 'ctx' as the ralloc owner.
*/
static s_expression *read_expression(void *ctx, const char *&src);
/**
* Print out an S-Expression. Useful for debugging.
*/
virtual void print() = 0;
virtual bool is_list() const { return false; }
virtual bool is_symbol() const { return false; }
virtual bool is_number() const { return false; }
virtual bool is_int() const { return false; }
protected:
s_expression() { }
};
/* Atoms */
class s_number : public s_expression
{
public:
bool is_number() const { return true; }
virtual float fvalue() = 0;
protected:
s_number() { }
};
class s_int : public s_number
{
public:
s_int(int x) : val(x) { }
bool is_int() const { return true; }
float fvalue() { return float(this->val); }
int value() { return this->val; }
void print();
private:
int val;
};
class s_float : public s_number
{
public:
s_float(float x) : val(x) { }
float fvalue() { return this->val; }
void print();
private:
float val;
};
class s_symbol : public s_expression
{
public:
s_symbol(const char *, size_t);
bool is_symbol() const { return true; }
const char *value() { return this->str; }
void print();
private:
const char *str;
};
/* Lists of expressions: (expr1 ... exprN) */
class s_list : public s_expression
{
public:
s_list();
virtual bool is_list() const { return true; }
void print();
exec_list subexpressions;
};
// ------------------------------------------------------------
/**
* Part of a pattern to match - essentially a record holding a pointer to the
* storage for the component to match, along with the appropriate type.
*/
class s_pattern {
public:
s_pattern(s_expression *&s) : p_expr(&s), type(EXPR) { }
s_pattern(s_list *&s) : p_list(&s), type(LIST) { }
s_pattern(s_symbol *&s) : p_symbol(&s), type(SYMBOL) { }
s_pattern(s_number *&s) : p_number(&s), type(NUMBER) { }
s_pattern(s_int *&s) : p_int(&s), type(INT) { }
s_pattern(const char *str) : literal(str), type(STRING) { }
bool match(s_expression *expr);
private:
union {
s_expression **p_expr;
s_list **p_list;
s_symbol **p_symbol;
s_number **p_number;
s_int **p_int;
const char *literal;
};
enum { EXPR, LIST, SYMBOL, NUMBER, INT, STRING } type;
};
bool
s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial);
#endif /* S_EXPRESSION_H */
|
