/media/sda-magnetic/david/compilerbau/pattern-matching/1th-episode/reg19.c

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

struct parsing_begin_end_state {
    int begin;
    int end;
};

//char expr [] = "(a(((+bc(d))l+ll)de(faaa)))zzz";
#define MAX_STATES  1024
#define END           -1
char expr [] = "abc*de[f,asddsr]sdsda*ghijk";
int i = 0;
int j;
int state1 [MAX_STATES];
int state2 [MAX_STATES];
char statechar [MAX_STATES];

char gettoken () {
    return expr [i++];
}
void tokenback () {
    i--;
}

/*
aaaa
aaaaaa
aaaaaaa
aaaaaaaa()
*/

int stream (struct parsing_begin_end_state);
int followed (struct parsing_begin_end_state);
int compound (struct parsing_begin_end_state);
int or_operator (struct parsing_begin_end_state);
int repeat_operator (struct parsing_begin_end_state);

int or_operator (struct parsing_begin_end_state be_arg) {
    int j1, j2, j3;
    int t;
    struct parsing_begin_end_state be;
    be.begin = -1;
    be.end = -1;
    struct parsing_begin_end_state TO_SUBS;
    
    if (gettoken () == '[') {
        j3 = j;
        j++;
        j1 = repeat_operator (TO_SUBS);
        if (gettoken () != ',') {
            fprintf (stderr, "Komma vergessen");
            exit (1);
        }
        j2 = repeat_operator (TO_SUBS);
        if (gettoken () != ']') {
            fprintf (stderr, "Klammer vergessen ]");
            exit (1);
        }
        state1 [j3] = j1;
        state2 [j3] = j2;
        statechar [j3] = '#';
        j3 = repeat_operator (TO_SUBS);
        if (state1 [j1] == END)
            state1 [j1] = j3;
        state2 [j1] = j3;
        if (state1 [j2] == END)
            state1 [j2] = j3;
        state2 [j2] = j3;
    }
    else { 
        tokenback ();
        j3 = repeat_operator (TO_SUBS);
    }
return j3;
}

int repeat_operator (struct parsing_begin_end_state be_arg) {
    int j1;
    struct parsing_begin_end_state be;
    be.begin = -1;
    be.end = -1;
    struct parsing_begin_end_state TO_SUBS;
    
    if (gettoken () == '*') {
        be.begin = j;
        be.end = j;
        j1 = stream (be);
    }
    else { 
        tokenback ();
        j1 = stream (be);
    }
return j1;
}

int stream (struct parsing_begin_end_state be_arg) {
    struct parsing_begin_end_state be;
    be.begin = -1;
    be.end = -1;
    struct parsing_begin_end_state TO_SUBS;

    compound (TO_SUBS);
    return followed (be_arg);
}

int followed (struct parsing_begin_end_state be_arg) {    
    int j1, j2;
    int t;
    struct parsing_begin_end_state be;
    be.begin = -1;
    be.end = -1;
    struct parsing_begin_end_state TO_SUBS;

    
    int ch = gettoken ();
    if ((ch >= 'a') && (ch <= 'z')) {
        t = j;
        j++;
        if (be_arg.begin == -1)
            j2 = j1 = or_operator (TO_SUBS);
        else {
            j1 = or_operator (TO_SUBS);
            j2 = be_arg.begin;
        }
        state1 [t] = j1;
        state2 [t] = j2;
        statechar [t] = ch;
    }
    else {
        t = END;
        tokenback ();
    }
return t;
}

int compound (struct parsing_begin_end_state be_arg) {
    struct parsing_begin_end_state be;
    be.begin = -1;
    be.end = -1;
    struct parsing_begin_end_state TO_SUBS;

    if (gettoken () == '(') {
        or_operator (TO_SUBS);
        if (gettoken () != ')') {
            fprintf (stderr, "fehler klammer vergessen %c %i\n", expr [i], i);
            exit (1);
        }
    }
    else
        tokenback ();
}


void init_end () {
    int k;
    for (k = 0;  k < MAX_STATES;  k++) {
        state1 [k] = END;
        state2 [k] = END;
    }
        
}

int main (void) {
    int k;
        struct parsing_begin_end_state TO_SUBS;
init_end ();
    or_operator (TO_SUBS);
    
    
    
    for (k = 0;  k < 24;  k++) {
        printf ("statechar [%i] = %c\n", k, statechar [k]);
        printf ("state1 [%i] = %i\n", k, state1 [k]);
        printf ("state2 [%i] = %i\n", k, state2 [k]);
    }
    
}