Special Symbols

Hash is a namespace identifier.
# Root ## Parent
Alpha identifies left arguments of dfns/dops.
Left Argument ⍺⍺ Left Operand
Omega identifies right arguments of dfns/dops.
Right Argument ⍵⍵ Right Operand
Del is used for self-reference in dfns/dops (as well as for the traditional APL Line Editor).
Function Self ∇∇ Operator Self
Quotation marks are used to surround character strings.
' APL Quote '' Empty Vector
Diamond character is used to separate APL statements on one line.
Statement Separator
Lamp symbol is used to identify following comments.
Comment Symbol
Colon is used to indicate end of line label or start of control word. It is also used in dfns and dops to separate the test from the expression in a Guard and Error Guard (two colons).
: End of Label : Start Control Word
Boolean: Expression Error Number(s):: Expression
Semicolon is used to separate index selection arrays in simple indexing, and to separate local names in the header of dfns/dops.
; Index Separator ; Localize Name
High Minus or Overbar is used to indicate that a number is negative.
¯ Negative


The following National Language characters may be used in names:

   À Ä Å Æ É Ñ Ö Ø Ü ß 
   à á â ä å æ ç è é ê ë
   í î ï ñ ó ô ö ø ù ú û ü

The three special characters

   _ ∆ ⍙

can also be used in names.