[Snowball-discuss] {'p','r','o','b','l','e','m'}

[Martin Porter]

[to Richard Boulton]

Richard,

I've hit a slight snag in converting strings "abc" to structures
{'a','b','c'}, in the ANSI C generated from Snowball, which is exemplified
by this little program:


#include <stdio.h>

struct among
{   int s_size;     /* number of chars in string */
    char * s;       /* search string */
    int substring_i;/* index to longest matching substring */
    int result;     /* result of the lookup */
    int (* function)(void);
};

static struct among A[4] =

{ { 4, "Abcd", 12, 12, 0},
  { 4, "aBcd", 12, 12, 0},
  { 4, "abCd", 12, 12, 0},
  { 4, "abcD", 12, 12, 0}
};

static struct among B[4] =

{ { 4, {'A','b','c','d',0}, 12, 12, 0},
  { 4, {'a','B','c','d',0}, 12, 12, 0},
  { 4, {'a','B','C','d',0}, 12, 12, 0},
  { 4, {'a','b','c','D',0}, 12, 12, 0}
};

main(int argc, char * argv[])
{
    printf("%s\n", (A[1]).s);
    printf("%s\n", (B[1]).s);
    return 0;
}

A[4] has a valid initializer; B[4] does not. It is an oddity of C that
strings are treated differently from the character arrays they represent. B
only gets initialized correctly if the among structure is given as

    ....
    char s[100]; /* wasting space */
    ....

- very clumsy! And of course no finite upper bound is acceptable here.

The only solution seems to be to declare all strings in the form

static const symbol string_N[4] = {'a','b','c','d'};

and have a separate initialisation for all the among structures:

    A[0].s = string_1;
    A[1].s = string_2;

which I can do, but its disappointing that a small extension to Snowball
requires all this reorganisation. The generated code is also much less
attractive of course.

I thought I'd run this by you to make sure I wasn't missing anything
obvious. Assuming not I'll rework the generated ANSI C so that strings "..."
disappear entirely. (*sigh*)

Martin



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