complab9 JSON Flex

%option noyywrap bison-bridge bison-locations

%{

#include <stdio.h>
#include <stdlib.h>

#define TAG_IDENT       1
#define TAG_NUMBER      2
#define TAG_STRING      3
#define TAG_ERROR       4
#define TAG_TRUE        5
#define TAG_FALSE       6
#define TAG_NULL        7
#define TAG_OBJ_BEG     8
#define TAG_OBJ_END     9
#define TAG_ARR_BEG     10
#define TAG_ARR_END     11
#define TAG_SYM_COMMA     12
#define TAG_SYM_COLON     13

char *tag_names[] = {
    "END_OF_PROGRAM",
    "IDENT", "NUMBER", "STRING", "ERROR",
    "TRUE", "FALSE", "NULL",
    "OBJ_BEG", "OBJ_END",
    "ARR_BEG", "ARR_END",
    "SYM_COMMA", "SYM_COLON"
};

struct Position {
    int line, pos, index;
};

void print_pos(struct Position *p) {
    printf("(%d, %d)", p->line, p->pos);
}

struct Fragment {
    struct Position starting, following;
};

typedef struct Fragment YYLTYPE;

void print_frag(struct Fragment *f) {
    print_pos(&(f->starting));
    printf(" - ");
    print_pos(&(f->following));
}

union Token {
    char *tokenName;
};

typedef union Token YYSTYPE;

int continued;
struct Position cur;

#define YY_USER_ACTION                  \
{                                       \
    int i;                              \
    if (!continued)                     \
        yylloc->starting = cur;         \
    continued = 0;                      \
    for (i = 0; i < yyleng; i++) {      \
        if ('\n' == yytext[i]) {        \
            cur.line++;                 \
            cur.pos = 1;                \
        }                               \
        else                            \
            cur.pos++;                  \
        cur.index++;                    \
    }                                   \
    yylloc->following = cur;            \
}                                       \

void init_scanner(char *program) {
    continued = 0;
    cur.line = 1;
    cur.pos = 1;
    cur.index = 0;
    yy_scan_string(program);
}

void err(char *msg) {
    printf("Error ");
    print_pos(&cur);
    printf(": %s\n", msg);
}

%}

QUOTE       ["]
CHAR        [a-zA-Z0-9_\/\\.]
CHARS       {CHAR}+
STRING      {QUOTE}{QUOTE}|{QUOTE}{CHARS}{QUOTE}
DIGIT       [0-9]
DIGIT1TO9   [1-9]
DIGITS      {DIGIT}+
INT         {DIGIT}|{DIGIT1TO9}{DIGITS}|-{DIGIT}|-{DIGIT1TO9}{DIGITS}
FRAC        [.]{DIGITS}
E           [eE][+-]?
EXP         [E]{DIGITS}
NUMBER      {INT}|{INT}{FRAC}|{INT}{EXP}|{INT}{FRAC}{EXP}


%%

[ \n\t]+    /*ignore ws*/

true        { yylval->tokenName = yytext; return TAG_TRUE; }

false       { yylval->tokenName = yytext; return TAG_FALSE; }

null        { yylval->tokenName = yytext; return TAG_NULL; }

{STRING}    { yylval->tokenName = yytext; return TAG_STRING; }

{NUMBER}    { yylval->tokenName = yytext; return TAG_NUMBER; }

\{          { yylval->tokenName = yytext; return TAG_OBJ_BEG; }

\}          { yylval->tokenName = yytext; return TAG_OBJ_END; }

\[          { yylval->tokenName = yytext; return TAG_ARR_BEG; }

\]          { yylval->tokenName = yytext; return TAG_ARR_END; }

:           { yylval->tokenName = yytext; return TAG_SYM_COLON; }

,           { yylval->tokenName = yytext; return TAG_SYM_COMMA; }

<<EOF>>     return 0;

.           {
               err("Unexpected character");
               return TAG_ERROR;
            }

%%

#define PROGRAM "{ \"scripts\": [\"jquery.js\", \"background.js\"], \"persistent\": false }"

int main()
{
    int tag;
    YYSTYPE value;
    YYLTYPE coords;

    init_scanner(PROGRAM);

    do {
        tag = yylex(&value, &coords);
        if (0 != tag && TAG_ERROR != tag) {
          printf("%s ", tag_names[tag]);
            print_frag(&coords);
            printf(": %s\n", value.tokenName);
        }
    } while (0 != tag);

    return 0;
}