49 lines
1.0 KiB
C
49 lines
1.0 KiB
C
/* Function type. */
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typedef double (func_t) (double);
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/* Data type for links in the chain of symbols. */
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struct symrec
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{
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char *name; /* name of symbol */
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int type; /* type of symbol: either VAR or FUN */
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union
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{
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double var; /* value of a VAR */
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func_t *fun; /* value of a FUN */
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} value;
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struct symrec *next; /* link field */
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};
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typedef struct symrec symrec;
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/* The symbol table: a chain of 'struct symrec'. */
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extern symrec *sym_table;
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symrec *putsym (char const *name, int sym_type);
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symrec *getsym (char const *name);
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struct init
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{
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char const *name;
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func_t *fun;
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};
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struct init const funs[] =
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{
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{ "atan", atan },
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{ "cos", cos },
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{ "exp", exp },
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{ "ln", log },
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{ "sin", sin },
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{ "sqrt", sqrt },
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{ 0, 0 },
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};
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/* The symbol table: a chain of 'struct symrec'. */
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symrec *sym_table;
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/* Put functions in table. */
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static void
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init_table (void)
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{
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for (int i = 0; funs[i].name; i++)
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{
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symrec *ptr = putsym (funs[i].name, FUN);
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ptr->value.fun = funs[i].fun;
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}
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}
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