contrib/tre/lib/tre-ast.h

   1 /*
   2   tre-ast.h - Abstract syntax tree (AST) definitions
   3
   4   This software is released under a BSD-style license.
   5   See the file LICENSE for details and copyright.
   6
   7 */
   8
   9
  10 #ifndef TRE_AST_H
  11 #define TRE_AST_H 1
  12
  13 #include <limits.h>
  14
  15 #include "tre-mem.h"
  16 #include "tre-internal.h"
  17 #include "tre-compile.h"
  18
  19 /* The different AST node types. */
  20 typedef enum {
  21   LITERAL,
  22   CATENATION,
  23   ITERATION,
  24   UNION
  25 } tre_ast_type_t;
  26
  27 /* Special subtypes of TRE_LITERAL. */
  28 #define EMPTY     -1   /* Empty leaf (denotes empty string). */
  29 #define ASSERTION -2   /* Assertion leaf. */
  30 #define TAG       -3   /* Tag leaf. */
  31 #define BACKREF   -4   /* Back reference leaf. */
  32 #define PARAMETER -5   /* Parameter. */
  33
  34 #define IS_SPECIAL(x)   ((x)->code_min < 0)
  35 #define IS_EMPTY(x)     ((x)->code_min == EMPTY)
  36 #define IS_ASSERTION(x) ((x)->code_min == ASSERTION)
  37 #define IS_TAG(x)       ((x)->code_min == TAG)
  38 #define IS_BACKREF(x)   ((x)->code_min == BACKREF)
  39 #define IS_PARAMETER(x) ((x)->code_min == PARAMETER)
  40
  41 #define SUBMATCH_ID_INVISIBLE_START     (INT_MAX / 2 + 1)
  42
  43
  44 /* A generic AST node.  All AST nodes consist of this node on the top
  45    level with `obj' pointing to the actual content. */
  46 typedef struct _tre_ast_node {
  47   void *obj;             /* Pointer to actual node. */
  48   tre_last_matched_branch_pre_t *last_matched_branch;
  49   tre_last_matched_pre_t *last_matched_in_progress;
  50   tre_pos_and_tags_t *firstpos;
  51   tre_pos_and_tags_t *lastpos;
  52   /* The original pointer is used to point to the original node, when a
  53    * CATENATION and tag are added.  If NULL, this is node is the original */
  54   struct _tre_ast_node *original;
  55   tre_ast_type_t type;   /* Type of the node. */
  56   int submatch_id;
  57   int num_submatches;
  58   int num_tags;
  59   short nullable;
  60   short make_branches;
  61 } tre_ast_node_t;
  62
  63
  64 /* A "literal" node.  These are created for assertions, back references,
  65    tags, matching parameter settings, and all expressions that match one
  66    character. */
  67 typedef struct {
  68   tre_cint_t code_min;
  69   tre_cint_t code_max;
  70   int position;
  71   union {
  72     tre_bracket_match_list_t *bracket_match_list;
  73     int *params;
  74   } u;
  75 } tre_literal_t;
  76
  77 /* A "catenation" node.  These are created when two regexps are concatenated.
  78    If there are more than one subexpressions in sequence, the `left' part
  79    holds all but the last, and `right' part holds the last subexpression
  80    (catenation is left associative). */
  81 typedef struct {
  82   tre_ast_node_t *left;
  83   tre_ast_node_t *right;
  84 } tre_catenation_t;
  85
  86 /* An "iteration" node.  These are created for the "*", "+", "?", and "{m,n}"
  87    operators. */
  88 typedef struct {
  89   /* Subexpression to match. */
  90   tre_ast_node_t *arg;
  91   /* Minimum number of consecutive matches. */
  92   int min;
  93   /* Maximum number of consecutive matches. */
  94   int max;
  95   /* If 0, match as many characters as possible, if 1 match as few as
  96      possible.  Note that this does not always mean the same thing as
  97      matching as many/few repetitions as possible. */
  98   unsigned int minimal:1;
  99   /* Approximate matching parameters (or NULL). */
 100   int *params;
 101 } tre_iteration_t;
 102
 103 /* An "union" node.  These are created for the "|" operator. */
 104 typedef struct {
 105   tre_ast_node_t *left;
 106   tre_ast_node_t *right;
 107   /* The left end right end tags if non-zero */
 108   int left_tag;
 109   int right_tag;
 110 } tre_union_t;
 111
 112 tre_ast_node_t *
 113 tre_ast_new_node(tre_mem_t mem, tre_ast_type_t type, size_t size);
 114
 115 tre_ast_node_t *
 116 tre_ast_new_literal(tre_mem_t mem, int code_min, int code_max, int position);
 117
 118 tre_ast_node_t *
 119 tre_ast_new_iter(tre_mem_t mem, tre_ast_node_t *arg, int min, int max,
 120                  int minimal);
 121
 122 tre_ast_node_t *
 123 tre_ast_new_union(tre_mem_t mem, tre_ast_node_t *left, tre_ast_node_t *right);
 124
 125 tre_ast_node_t *
 126 tre_ast_new_catenation(tre_mem_t mem, tre_ast_node_t *left,
 127                        tre_ast_node_t *right);
 128
 129 #ifdef TRE_DEBUG
 130 void
 131 tre_ast_print(tre_ast_node_t *tree);
 132
 133 /* XXX - rethink AST printing API */
 134 void
 135 tre_print_params(int *params);
 136 #endif /* TRE_DEBUG */
 137
 138 #endif /* TRE_AST_H */
 139
 140 /* EOF */