*/
%{
-extern int yylex(void);
-void yyerror(const char *);
-struct graph_node *
-node_exists(struct graph_node *, struct graph_node *);
-struct graph_node *
-node_replace(struct graph_node *, struct graph_node *);
-char *
-doc_next(void);
+#define YYDEBUG 1 // compile with debugging facilities
+%}
-#define DECIMAL_STRLEN_MAX 20
+/* names for generated header and parser files */
+%defines "command_parse.h"
+%output "command_parse.c"
-// compile with debugging facilities
-#define YYDEBUG 1
-%}
+/* required external units */
%code requires {
#include "command.h"
#include "command_graph.h"
#include "memory.h"
-}
-%code provides {
+
+ extern int
+ yylex(void);
+
extern void
set_buffer_string(const char *);
+}
+
+/* functionality this unit exports */
+%code provides {
struct graph_node *
parse_command_format(struct graph_node *, struct cmd_element *);
-}
+ /* maximum length of a number, lexer will not match anything longer */
+ #define DECIMAL_STRLEN_MAX 20
+}
-/* valid types for tokens */
-%union{
- long long integer;
+/* valid semantic types for tokens and rules */
+%union {
+ long long number;
char *string;
struct graph_node *node;
}
-/* some helpful state variables */
-%{
-struct graph_node *startnode, // command root node
- *currnode, // current node
- *seqhead; // sequence head
-
-
-struct graph_node *optnode_start, // start node for option set
- *optnode_end; // end node for option set
-
-struct graph_node *selnode_start, // start node for selector set
- *selnode_end; // end node for selector set
-
-struct cmd_element *command; // command we're parsing
-char *docstring;
-%}
-
+/* union types for lexed tokens */
%token <string> WORD
%token <string> IPV4
%token <string> IPV4_PREFIX
%token <string> IPV6_PREFIX
%token <string> VARIABLE
%token <string> RANGE
-%token <integer> NUMBER
+%token <number> NUMBER
+/* union types for parsed rules */
%type <node> start
%type <node> sentence_root
%type <node> literal_token
%type <node> selector_token
%type <node> selector_token_seq
-%defines "command_parse.h"
-%output "command_parse.c"
+%code {
+ /* bison declarations */
+ void
+ yyerror(struct cmd_element *el, struct graph_node *sn, char const *msg);
+
+ /* state variables for a single parser run */
+ struct graph_node *currnode, // current position in DFA
+ *seqhead; // sequence head
+
+ struct graph_node *optnode_start, // start node for option set
+ *optnode_end; // end node for option set
+
+ struct graph_node *selnode_start, // start node for selector set
+ *selnode_end; // end node for selector set
+
+ char *docstr_start, *docstr; // pointers to copy of command docstring
+
+ /* helper functions for parser */
+ static char *
+ doc_next(void);
+
+ static struct graph_node *
+ node_exists(struct graph_node *, struct graph_node *);
+
+ static struct graph_node *
+ node_replace(struct graph_node *, struct graph_node *);
+
+ static int
+ cmp_node(struct graph_node *, struct graph_node *);
+
+ static void
+ terminate_graph (struct graph_node *,
+ struct graph_node *,
+ struct cmd_element *);
+
+ static void
+ cleanup(void);
+}
+
+/* yyparse parameters */
+%parse-param { struct cmd_element *element }
+%parse-param { struct graph_node *startnode }
+
+/* called automatically before yyparse */
+%initial-action {
+ /* clear state pointers */
+ seqhead = NULL;
+ currnode = NULL;
+ selnode_start = selnode_end = NULL;
+ optnode_start = optnode_end = NULL;
+
+ /* set string to parse */
+ set_buffer_string(element->string);
+
+ /* copy docstring and keep a pointer to the copy */
+ docstr = element->doc ? XSTRDUP(MTYPE_TMP, element->doc) : NULL;
+ docstr_start = docstr;
+}
-/* grammar proper */
%%
start:
sentence_root cmd_token_seq
{
- // create leaf node
- struct graph_node *end = new_node(END_GN);
- end->element = command;
-
- // add node
- if (node_exists(currnode, end))
- {
- yyerror("Duplicate command.");
- YYABORT;
- }
- add_node(currnode, end);
- fprintf(stderr, "Parsed full command successfully.\n");
+ // tack on the command element
+ terminate_graph (startnode, currnode, element);
+ cleanup();
}
| sentence_root cmd_token_seq '.' placeholder_token
{
// wth normal command termination procedure
node_replace(currnode, currnode);
- // create leaf node
- struct graph_node *end = new_node(END_GN);
- end->element = command;
-
- // add node
- if (node_exists(currnode, end))
- {
- yyerror("Duplicate command.");
- YYABORT;
- }
- add_node(currnode, end);
- fprintf(stderr, "Parsed full command successfully.\n");
+ // tack on the command element
+ terminate_graph (startnode, currnode, element);
+ cleanup();
}
sentence_root: WORD
$$ = currnode;
};
-/* valid top level tokens */
cmd_token:
placeholder_token
{
$$->max = strtoll( yylval.string, &yylval.string, 10 );
// validate range
- if ($$->min >= $$->max) yyerror("Invalid range.");
+ if ($$->min >= $$->max) yyerror(element, startnode, "Invalid range.");
free ($1);
}
| NUMBER
{
$$ = new_node(NUMBER_GN);
- $$->value = yylval.integer;
+ $$->value = yylval.number;
$$->text = XCALLOC(MTYPE_CMD_TOKENS, DECIMAL_STRLEN_MAX+1);
snprintf($$->text, DECIMAL_STRLEN_MAX, "%lld", $$->value);
$$->doc = doc_next();
;
/* <selector|set> productions */
-selector:
- '<' selector_part '>'
+selector: '<' selector_part '>'
{
// all the graph building is done in selector_element,
// so just return the selector subgraph head
| selector_element '|' selector_element
;
-selector_element:
- selector_element_root selector_token_seq
+selector_element: selector_element_root selector_token_seq
{
// if the selector start and end do not exist, create them
if (!selnode_start || !selnode_end) { // if one is null
%%
-void yyerror(char const *message) {
- // fail on bad parse
- fprintf(stderr, "Grammar error: %s\n", message);
+struct graph_node *
+parse_command_format(struct graph_node *start, struct cmd_element *cmd)
+{
+ yydebug = 0;
+
+ // parse command into DFA
+ yyparse(cmd, start);
+
+ return start;
+}
+
+/* parser helper functions */
+
+void
+yyerror(struct cmd_element *el, struct graph_node *sn, char const *msg)
+{
+ fprintf(stderr, "Grammar error: %s\n", msg);
exit(EXIT_FAILURE);
}
-struct graph_node *
-parse_command_format(struct graph_node *start, struct cmd_element *cmd)
+static void
+cleanup()
{
- fprintf(stderr, "parsing: %s\n", cmd->string);
+ /* free resources */
+ free (docstr_start);
/* clear state pointers */
- startnode = start;
- currnode = seqhead = NULL;
+ seqhead = NULL;
+ currnode = NULL;
+ docstr_start = docstr = NULL;
selnode_start = selnode_end = NULL;
optnode_start = optnode_end = NULL;
+}
- // trace parser
- yydebug = 0;
- // command element
- command = cmd;
- // copy docstring and keep a pointer to the copy
- char *doc = docstring = cmd->doc ? XSTRDUP(MTYPE_TMP, cmd->doc) : NULL;
- // make flex read from a string
- set_buffer_string(command->string);
- // parse command into DFA
- yyparse();
- // cleanup
- free (doc);
- doc = NULL;
- // startnode points to command DFA
- return startnode;
+static void
+terminate_graph (struct graph_node *startnode,
+ struct graph_node *finalnode,
+ struct cmd_element *element)
+{
+ struct graph_node *end = new_node(END_GN);
+ end->element = element;
+ if (node_exists(finalnode, end))
+ yyerror(element, startnode, "Duplicate command.");
+ else
+ add_node(finalnode, end);
}
-struct graph_node *
+static char *
+doc_next()
+{
+ char *piece = NULL;
+ if (!docstr || !(piece = strsep(&docstr, "\n")))
+ return NULL;
+ return XSTRDUP(MTYPE_CMD_TOKENS, piece);
+}
+
+static struct graph_node *
node_exists(struct graph_node *parent, struct graph_node *child)
{
struct graph_node *p_child;
return NULL;
}
-struct graph_node *
+static struct graph_node *
node_replace(struct graph_node *parent, struct graph_node *child)
{
struct graph_node *existing = node_exists (parent, child);
- if (!existing)
- existing = add_node(parent, child);
-
- return existing;
+ return existing ? existing : add_node(parent, child);
}
-char *
-doc_next()
+static int
+cmp_node(struct graph_node *first, struct graph_node *second)
{
- char *piece = NULL;
- if (!docstring || !(piece = strsep(&docstring, "\n")))
- return NULL;
- return XSTRDUP(MTYPE_CMD_TOKENS, piece);
+ // compare types
+ if (first->type != second->type) return 0;
+
+ switch (first->type) {
+ case WORD_GN:
+ case VARIABLE_GN:
+ if (first->text && second->text) {
+ if (strcmp(first->text, second->text)) return 0;
+ }
+ else if (first->text != second->text) return 0;
+ break;
+ case RANGE_GN:
+ if (first->min != second->min || first->max != second->max)
+ return 0;
+ break;
+ case NUMBER_GN:
+ if (first->value != second->value) return 0;
+ break;
+ /* selectors and options should be equal if all paths are equal,
+ * but the graph isomorphism problem is not solvable in polynomial
+ * time so we consider selectors and options inequal in all cases;
+ * ultimately this forks the graph
+ */
+ case SELECTOR_GN:
+ case OPTION_GN:
+ return 0;
+ /* end nodes are always considered equal, since each node may only
+ * have one at a time
+ */
+ case START_GN:
+ case END_GN:
+ case NUL_GN:
+ default:
+ break;
+ }
+ return 1;
}
projects / matthieu / frr.git / commitdiff