1/* -*- c++ -*- */
2/*
3 * Copyright © 2010 Intel Corporation
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 */
24
25#pragma once
26#ifndef S_EXPRESSION_H
27#define S_EXPRESSION_H
28
29#include "main/core.h" /* for Elements */
30#include "strtod.h"
31#include "list.h"
32
33/* Type-safe downcasting macros (also safe to pass NULL) */
34#define SX_AS_(t,x) ((x) && ((s_expression*) x)->is_##t()) ? ((s_##t*) (x)) \
35                                                           : NULL
36#define SX_AS_LIST(x)   SX_AS_(list, x)
37#define SX_AS_SYMBOL(x) SX_AS_(symbol, x)
38#define SX_AS_NUMBER(x) SX_AS_(number, x)
39#define SX_AS_INT(x)    SX_AS_(int, x)
40
41/* Pattern matching macros */
42#define MATCH(list, pat) s_match(list, Elements(pat), pat, false)
43#define PARTIAL_MATCH(list, pat) s_match(list, Elements(pat), pat, true)
44
45/* For our purposes, S-Expressions are:
46 * - <int>
47 * - <float>
48 * - symbol
49 * - (expr1 expr2 ... exprN)     where exprN is an S-Expression
50 *
51 * Unlike LISP/Scheme, we do not support (foo . bar) pairs.
52 */
53class s_expression : public exec_node
54{
55public:
56   /**
57    * Read an S-Expression from the given string.
58    * Advances the supplied pointer to just after the expression read.
59    *
60    * Any allocation will be performed with 'ctx' as the ralloc owner.
61    */
62   static s_expression *read_expression(void *ctx, const char *&src);
63
64   /**
65    * Print out an S-Expression.  Useful for debugging.
66    */
67   virtual void print() = 0;
68
69   virtual bool is_list()   const { return false; }
70   virtual bool is_symbol() const { return false; }
71   virtual bool is_number() const { return false; }
72   virtual bool is_int()    const { return false; }
73
74protected:
75   s_expression() { }
76};
77
78/* Atoms */
79
80class s_number : public s_expression
81{
82public:
83   bool is_number() const { return true; }
84
85   virtual float fvalue() = 0;
86
87protected:
88   s_number() { }
89};
90
91class s_int : public s_number
92{
93public:
94   s_int(int x) : val(x) { }
95
96   bool is_int() const { return true; }
97
98   float fvalue() { return float(this->val); }
99   int value() { return this->val; }
100
101   void print();
102
103private:
104   int val;
105};
106
107class s_float : public s_number
108{
109public:
110   s_float(float x) : val(x) { }
111
112   float fvalue() { return this->val; }
113
114   void print();
115
116private:
117   float val;
118};
119
120class s_symbol : public s_expression
121{
122public:
123   s_symbol(const char *, size_t);
124
125   bool is_symbol() const { return true; }
126
127   const char *value() { return this->str; }
128
129   void print();
130
131private:
132   const char *str;
133};
134
135/* Lists of expressions: (expr1 ... exprN) */
136class s_list : public s_expression
137{
138public:
139   s_list();
140
141   virtual bool is_list() const { return true; }
142
143   void print();
144
145   exec_list subexpressions;
146};
147
148// ------------------------------------------------------------
149
150/**
151 * Part of a pattern to match - essentially a record holding a pointer to the
152 * storage for the component to match, along with the appropriate type.
153 */
154class s_pattern {
155public:
156   s_pattern(s_expression *&s) : p_expr(&s),   type(EXPR)   { }
157   s_pattern(s_list       *&s) : p_list(&s),   type(LIST)   { }
158   s_pattern(s_symbol     *&s) : p_symbol(&s), type(SYMBOL) { }
159   s_pattern(s_number     *&s) : p_number(&s), type(NUMBER) { }
160   s_pattern(s_int        *&s) : p_int(&s),    type(INT)    { }
161   s_pattern(const char *str)  : literal(str), type(STRING) { }
162
163   bool match(s_expression *expr);
164
165private:
166   union {
167      s_expression **p_expr;
168      s_list       **p_list;
169      s_symbol     **p_symbol;
170      s_number     **p_number;
171      s_int        **p_int;
172      const char *literal;
173   };
174   enum { EXPR, LIST, SYMBOL, NUMBER, INT, STRING } type;
175};
176
177bool
178s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial);
179
180#endif /* S_EXPRESSION_H */
181