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/*
\funcref{compare}{void compare (\params)}
{
{VAR\_} {lval} {left variable to compare}
{VAR\_} {rval} {right variable to compare}
}
{}
{}
{}
{compare.c}
{
This function compares two {\em VAR\_} type variables and pushes the
result of the comparison. Comparisons between different types (e.g.,
between a string and a list) should never occur, since the compiler
either generates opcodes for type casting or issues an error.
The comparison between non-list types is either an integer subtraction,
or a {\em strcmp()}. The comparison between two lists is performed as
follows:
\begin{itemize}
\item If the lists do not have the same size, then the list with
the bigger size is larger.
\item For all elements in the list, a string comparison is made.
made. If this comparison indicates non-zero, the list with the
alphabetically higher string is larger.
\end{itemize}
The return value of {\em compare()} is a {\em VAR\_} struct with type
{\em e\_int}. The {\em vu.intval} field is the result of comparison,
with the value $<0$ meaning that {\em rval} is larger; $>0$ meaning
that {\em lval} is larger, or $0$ meaning that {\em lval == rval}.
}
*/
#include "icm-exec.h"
void compare (lval, rval)
VAR_ lval, rval;
{
register unsigned
i;
register LIST_
*llist,
*rlist;
VAR_
ret;
ret.type = e_int;
if (lval.type & e_str)
ret.vu.intval = strcmp (lval.vu.i->ls.str, rval.vu.i->ls.str);
else if (lval.type & e_int)
ret.vu.intval = lval.vu.intval - rval.vu.intval;
else
{
ret.vu.intval = 0; /* assume equal */
llist = &(lval.vu.i->ls.list);
rlist = &(rval.vu.i->ls.list);
if (llist->size != rlist->size)
ret.vu.intval = llist->size - rlist->size;
else
for (i = 0; i < llist->size; i++)
if ( (ret.vu.intval = strcmp (llist->element [i],
rlist->element [i]))
)
break;
}
push (ret);
}
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