System Variable ELX

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⎕ELX - Error Latent Expression

⎕ELX Set action to take on error
⎕ELX←'string'

This system variable takes a string. That string is executed when the interpreter encounters an error. In particular the string may...

  • call a function
  • jump to a particular label

Note that ⎕ELX can be localized and set dynamically to whatever it needs to deal with errors appropriately.
An APL Interpreter error (such as 'Domain Error') which triggers ⎕ELX will also send a Diagnostic Error Message to
⎕DM, for debugging purposes, if needed by User. ⎕ELX is useful in situations when a known error occurs and the User Function
knows how to work around or deal with it appropriately by say branching to a special line of APL code.

See ALSO: ⎕EA Execute Alternate and Quad DM or ⎕DM


System Variables (A value may be assigned to these except for ⎕DM)
ALX CT DM DT ELX FC FEATURE FPC IC IO
LX PP PR PW RL SA WSID
Niladic System Functions (a value cannot be assigned to these)
A AV EM ET LC NNAMES NNUMS 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 are case insensitive


See Also
System Commands System Variables and Functions Operators
Keyboard
A+S
Alt ¨ ¯ < > × ÷
Sh ~ ! @ # $ % ^ & * ( ) _ +
Key ` 1 2 3 4 5 6 7 8 9 0 - =
A+S
Alt ? π
Sh Q W E R T Y U I O P { } |
Key q w e r t y u i o p [ ] \
A+S §
Alt
Sh A S D F G H J K L : "
Key a s d f g h j k l ; '
A+S
Alt
Sh Z X C V B N M < > ?
Key z x c v b n m , . /
NARS 2000 Lang
Tool
Bar
+ - × ÷ * ! ? |
= < >
~ § π .. ,
/ \ ¨ .
_ ¯ b e g p r v x