i_add integer addition (+) ck_null ifsT2 S S
subtract subtraction (-) ck_null IfsT2 S S
i_subtract integer subtraction (-) ck_null ifsT2 S S
-concat concatenation (.) or string ck_concat fsT2 S S
+concat concatenation (.) or string ck_concat fst2 S S
stringify string ck_fun fsT@ S
left_shift left bitshift (<<) ck_bitop fsT2 S S
splice splice ck_fun m@ A S? S? L
push push ck_fun imsT@ A L
-pop pop ck_shift s% A
-shift shift ck_shift s% A
+pop pop ck_shift s% A?
+shift shift ck_shift s% A?
unshift unshift ck_fun imsT@ A L
sort sort ck_sort m@ C? L
reverse reverse ck_fun mt@ L