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|
%{
#include "cmdtree.h"
extern int yylex(void);
extern void yyerror(const char *);
extern int cmd_parse_format(const char *, const char *);
extern void set_buffer_string(const char *);
// compile with debugging facilities
#define YYDEBUG 1
%}
%union{
int integer;
char *string;
struct graph_node *node;
}
%{
// last top-level node
struct graph_node *topnode, // command root node
*currnode; // current node
struct graph_node *optnode_start, // start node for option set
*optnode_end, // end node for option set
*optnode_el; // start node for an option set element
struct graph_node *selnode_start, // start node for selector set
*selnode_end, // end node for selector set
*selnode_el; // start node for an selector set element
%}
%token <string> WORD
%token <string> IPV4
%token <string> IPV4_PREFIX
%token <string> IPV6
%token <string> IPV6_PREFIX
%token <string> VARIABLE
%token <string> RANGE
%token <integer> NUMBER
%type <node> start
%type <node> sentence_root
%type <node> literal_token
%type <node> placeholder_token
%type <node> option_token
%type <node> selector_token
%type <node> option
%type <node> selector
%type <node> selector_token_seq
%type <node> option_token_seq
%defines "command_parse.h"
%output "command_parse.c"
/* grammar proper */
%%
start: sentence_root
cmd_token_seq;
sentence_root: WORD
{
currnode = new_node(WORD_GN);
currnode->is_root = 1;
add_node(topnode, currnode);
};
/* valid top level tokens */
cmd_token:
placeholder_token
{ currnode = add_node(currnode, $1); }
| literal_token
{ currnode = add_node(currnode, $1); }
| selector
{
add_node(currnode, selnode_start);
currnode = selnode_end;
}
| option
{
add_node(currnode, optnode_start);
currnode = optnode_end;
}
;
cmd_token_seq:
%empty
| cmd_token_seq cmd_token
;
placeholder_token:
IPV4 {$$ = new_node(IPV4_GN);}
| IPV4_PREFIX {$$ = new_node(IPV4_PREFIX_GN);}
| IPV6 {$$ = new_node(IPV6_GN);}
| IPV6_PREFIX {$$ = new_node(IPV6_PREFIX_GN);}
| VARIABLE {$$ = new_node(VARIABLE_GN);}
| RANGE {$$ = new_node(RANGE_GN);}
;
literal_token:
WORD {$$ = new_node(WORD_GN);}
| NUMBER {$$ = new_node(NUMBER_GN);}
;
/* <selector|token> productions */
selector:
'<' selector_part '|'
selector_element '>'
{
$$ = new_node(SELECTOR_GN);
// attach subtree here
};
selector_part:
selector_part '|' selector_element
| selector_element
;
selector_element:
WORD selector_token_seq;
selector_token_seq:
%empty {$$ = NULL;}
| selector_token_seq selector_token
{
currnode = add_node(currnode, $2);
}
;
selector_token:
literal_token
| placeholder_token
| option
;
/* [option|set] productions */
option: '[' option_part ']'
{
$$ = new_node(OPTION_GN);
// attach subtree here
};
option_part:
option_part '|' option_token_seq
| option_token_seq
;
option_token_seq:
option_token_seq option_token
| option_token
{
printf("Matched singular option token in sequence, type: %d\n", $1->type);
}
;
option_token:
literal_token
{
// optnode_el points to root of option element
if (optnode_el == NULL) {
optnode_el = $1;
currnode = $1;
}
else
add_node(currnode, $1);
}
| placeholder_token
{
// optnode_el points to root of option element
if (optnode_el == NULL) {
optnode_el = $1;
currnode = $1;
}
else
add_node(currnode, $1);
}
;
%%
int
main (void)
{
yydebug = 1;
const char* input = "show [random conf NAME] thing";
printf("Parsing:\n\t%s\n", input);
return cmd_parse_format(input, "description");
}
void yyerror(char const *message) {
printf("Grammar error: %s\n", message);
exit(EXIT_FAILURE);
}
int
cmd_parse_format(const char *string, const char *desc)
{
// make flex read from a string
set_buffer_string(string);
// initialize the start node of this command dfa
topnode = new_node(NUL_GN);
// parse command into DFA
yyparse();
// topnode points to command DFA
return 0;
}
|
