src/glsl/s_expression.h

   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  */
  53 class s_expression : public exec_node
  54 {
  55 public:
  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
  74 protected:
  75    s_expression() { }
  76 };
  77
  78 /* Atoms */
  79
  80 class s_number : public s_expression
  81 {
  82 public:
  83    bool is_number() const { return true; }
  84
  85    virtual float fvalue() = 0;
  86
  87 protected:
  88    s_number() { }
  89 };
  90
  91 class s_int : public s_number
  92 {
  93 public:
  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
 103 private:
 104    int val;
 105 };
 106
 107 class s_float : public s_number
 108 {
 109 public:
 110    s_float(float x) : val(x) { }
 111
 112    float fvalue() { return this->val; }
 113
 114    void print();
 115
 116 private:
 117    float val;
 118 };
 119
 120 class s_symbol : public s_expression
 121 {
 122 public:
 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
 131 private:
 132    char *str;
 133 };
 134
 135 /* Lists of expressions: (expr1 ... exprN) */
 136 class s_list : public s_expression
 137 {
 138 public:
 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  */
 154 class s_pattern {
 155 public:
 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
 165 private:
 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
 177 bool
 178 s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial);
 179
 180 #endif /* S_EXPRESSION_H */