istart            832 src/string.c       int istart, iend;
istart            835 src/string.c           istart = 0;
istart            839 src/string.c           istart = SCM_INT_VALUE(start);
istart            843 src/string.c           if (istart == 0) return SCM_OBJ(x);
istart            850 src/string.c       return substring(xb, istart, iend);