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 "list.h"
  30
  31 #define SX_AS_(t,x) ((x) && ((s_expression*) x)->is_##t()) ? ((s_##t*) (x)) \
  32                                                            : NULL
  33 #define SX_AS_LIST(x)   SX_AS_(list, x)
  34 #define SX_AS_SYMBOL(x) SX_AS_(symbol, x)
  35 #define SX_AS_NUMBER(x) SX_AS_(number, x)
  36 #define SX_AS_INT(x)    SX_AS_(int, x)
  37
  38 /* For our purposes, S-Expressions are:
  39  * - <int>
  40  * - <float>
  41  * - symbol
  42  * - (expr1 expr2 ... exprN)     where exprN is an S-Expression
  43  *
  44  * Unlike LISP/Scheme, we do not support (foo . bar) pairs.
  45  */
  46 class s_expression : public exec_node
  47 {
  48 public:
  49    virtual ~s_expression() { }
  50
  51    /**
  52     * Read an S-Expression from the given string.
  53     * Advances the supplied pointer to just after the expression read.
  54     */
  55    static s_expression *read_expression(const char *&src);
  56
  57    /**
  58     * Print out an S-Expression.  Useful for debugging.
  59     */
  60    virtual void print() = 0;
  61
  62    virtual bool is_list()   const { return false; }
  63    virtual bool is_symbol() const { return false; }
  64    virtual bool is_number() const { return false; }
  65    virtual bool is_int()    const { return false; }
  66
  67 protected:
  68    s_expression() { }
  69 };
  70
  71 /* Atoms */
  72
  73 class s_number : public s_expression
  74 {
  75 public:
  76    virtual ~s_number() { }
  77
  78    bool is_number() const { return true; }
  79
  80    virtual float fvalue() = 0;
  81
  82 protected:
  83    s_number() { }
  84 };
  85
  86 class s_int : public s_number
  87 {
  88 public:
  89    s_int(int x) : val(x) { }
  90    virtual ~s_int() { }
  91
  92    bool is_int() const { return true; }
  93
  94    float fvalue() { return float(this->val); }
  95    int value() { return this->val; }
  96
  97    void print();
  98
  99 private:
 100    int val;
 101 };
 102
 103 class s_float : public s_number
 104 {
 105 public:
 106    s_float(float x) : val(x) { }
 107    virtual ~s_float() { }
 108
 109    float fvalue() { return this->val; }
 110
 111    void print();
 112
 113 private:
 114    float val;
 115 };
 116
 117 class s_symbol : public s_expression
 118 {
 119 public:
 120    s_symbol(const char *);
 121    virtual ~s_symbol();
 122
 123    bool is_symbol() const { return true; }
 124
 125    const char *value() { return this->str; }
 126
 127    void print();
 128
 129 private:
 130    char *str;
 131 };
 132
 133 /* Lists of expressions: (expr1 ... exprN) */
 134 class s_list : public s_expression
 135 {
 136 public:
 137    s_list();
 138    virtual ~s_list();
 139
 140    virtual bool is_list() const { return true; }
 141    unsigned length() const;
 142
 143    void print();
 144
 145    exec_list subexpressions;
 146 };
 147
 148 #endif /* S_EXPRESSION_H */