System Function CR
This function is available in both monadic and dyadic forms
Monadic Function


R is a character scalar or vector.  
Z is a character matrix with as many rows as there are lines in the function (including the header), and as many columns as the longest line (including the header). 
This monadic function behaves the same as described in the Extended APL Standard, except it also displays the canonical representation of an assigned function or operator.
For example,
f←,∘⍋∘⍋∘, ⍴⎕←⎕CR 'f' ,∘⍋∘⍋∘, 1 7 f←{⍺+⍵} ⍴⎕←⎕CR 'f' f←{⍺+⍵} 1 7
If the assigned function references an unnamed value which is not a simple scalar or vector, the representation shows a marker in that spot.
For example,
f←(2 3⍴'abcdef')∘⎕CR ⎕CR 'f' …∘⎕cr f←⎕CR ⎕CR 'f' f f 'f' f
Dyadic Function


R is a character scalar or vector.  
L is an integer scalar whose value is either 1 or 2. 
If the first character in R is #, then R is assumed to name an internal Magic Function; otherwise R is assumed to name a userdefined function/operator or a directly assigned function (e.g., f←+.×).
If L=2, then Z is a character matrix with as many rows as there are lines in the function (including the header), and as many columns as the longest line (including the header).
If L=1, then Z is either a simple character vector (for directly assigned functions), or a vector of character vectors (for userdefined functions/operators) with as many elements in Z as there are lines in the function (including the header), and each element of Z is a character vector representation of the corresponding line (or header) in the function.
For example,
f←+.× ⍴⎕←2 ⎕CR 'f' +.× 1 3 ⍴⎕←1 ⎕CR 'f' +.× 3 2 ⎕CR '#MonIota' Z←#MonIota R Z←⊃∘.,/⍳¨R 1 ⎕CR '#MonIota' Z←#MonIota R Z←⊃∘.,/⍳¨R
When this was written, the existing magic functions were named #MonIota, #DydIota, #MonDnShoe, #DydTilde, #MonRank, #DydRank, #Conform, #MonFMT, #Box, and #MonVR.
Note: ⎕CR is available as both a monadic and dyadic form system function, 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  ⎕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 