Search ('all' for everything):

Search results:
&ascii — ASCII characters
&cset — all characters
&digits — digits
&lcase — lowercase letters
&letters — letters
&ucase — uppercase letters
cset — convert to cset
x++x — compute cset or set union
x––x — compute cset or set difference
x∗∗x — cset or set intersection
~c1 — compute cset complement

Index of Function Types:
affects &pos
character sets
co-expressions
control structures
file processing
generators
infix operations
keywords
lists, sets and tables
math
metadata
output formatting
pattern matching
prefix operations
records
strings
windows and keyboards

Index of Subsystems:
base
digitcnt.icn
SNOBOL4 functions