System Function AT

Z←L ⎕AT R returns the attributes of the objects named in R.

R is a character scalar, vector, or matrix consisting of the names of objects (e.g., variables, functions, or operators).

L is an integer scalar whose value is either 1, 2, 3, or 4.

Z is an integer vector or matrix.

If R is a scalar, it is treated as the name; if R is a vector, it is treated as a vector of names separated from one another by one or more blanks; if R is a matrix, each row is treated as a single name surrounded by zero or more blanks.

If R consists of a single name, Z is a vector; otherwise Z is a matrix with as many rows as there are names in R.

The number of columns in Z depends upon the value of L.

• If L is 1, the result describes the Valences of the objects named in R and has three columns consisting of
  [1] Whether or not there is an Explicit result (1 or 0): This value is 1 for variables and for functions/operators that return a result; 0 otherwise.
  [2] The Function Valence (0, 1, or 2): This value is 0 for a non-function or for a niladic function, 1 for a monadic function or for a monadic derived function from an operator, and 2 for a dyadic or ambivalent function or for a dyadic or ambivalent derived function from an operator.
  [3] The Operator valence (0, 1, or 2): This value is 0 for a non-operator, 1 for a monadic operator, and 2 for a dyadic operator.

• If L is 2, the result describes the Fix Time of the objects named in R and has seven columns consisting of
  [1] Year
  [2] Month
  [3] Day
  [4] Hour
  [5] Minute
  [6] Second
  [7] Millisecond
  
  If an object named in R is not a user-defined function/operator, the corresponding row in the result is all 0. All times are in UTC and represent the time the function was last modified.

• If L is 3, the result describes the Execution Properties of the objects named in R and has four columns consisting of
  [1] Whether or not the object is Nondisplayable (1 or 0)
  [2] Whether or not the object is Nonsuspendable (1 or 0)
  [3] Whether or not the object Ignores weak interrupts, i.e. Ctrl-C or Ctrl-Break (1 or 0)
  [4] Whether or not the object Converts non-resource errors to DOMAIN ERRORs (this value is always 0)
  
  If an object named in R is a variable, the corresponding row in the result is all 0. If an object named in R is a primitive or system function, the corresponding row in the result is 1 1 1 0. If an object named in R is a function array, train, or magic function, the corresponding row in the result is 0 1 1 0.

• If L is 4, the result describes the Object Size of the objects named in R and has two columns consisting of
  [1] The object's size consisting of the object header and data sizes
  [2] The object's data size only.
  

⎕AT is a dyadic system function, which means you cannot assign a value to it.

System Variables (A value may be assigned to these except for ⎕DM)
⎕ALX	⎕CT	⎕DM	⎕DT	⎕ELX	⎕FC	⎕FEATURE	⎕FPC	⎕IC	⎕IO
⎕LR	⎕LX	⎕PP	⎕PR	⎕PW	⎕RL	⎕SA	⎕WSID
Niladic System Functions (a value cannot be assigned to these)
⎕A	⎕AV	⎕EM	⎕ET	⎕LC	⎕NNAMES	⎕NNUMS	⎕SI	⎕SYSID	⎕SYSVER
⎕T	⎕TC	⎕TCBEL	⎕TCBS	⎕TCESC	⎕TCFF	⎕TCHT	⎕TCLF	⎕TCNL	⎕TCNUL
⎕TS	⎕WA
Monadic or dyadic system functions (a value cannot be assigned to these)
⎕AT	⎕CR	⎕DC	⎕DFT	⎕DL	⎕DR	⎕EA	⎕EC	⎕ERROR	⎕ES
⎕EX	⎕FMT	⎕FX	⎕MF	⎕NAPPEND	⎕NC	⎕NCREATE	⎕NERASE	⎕NINFO	⎕NL
⎕NLOCK	⎕NREAD	⎕NRENAME	⎕NREPLACE	⎕NRESIZE	⎕NSIZE	⎕NTIE	⎕NUNTIE	⎕STOP	⎕TF
⎕TRACE	⎕UCS	⎕VR
Note that quad functions and variables (except for the ⎕A family of functions) are case insensitive