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 (.) 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
unpack unpack ck_fun @ S S
pack pack ck_fun mst@ S L
split split ck_split t@ S S S
-join join ck_join mst@ S L
+join join or string ck_join mst@ S L
# List operators.