IF-THEN-ELSE (Education Vector, April 1991, p.27)
Vector 8:2, page 19
Transcribed from the printed issue; not yet reviewed. Read it in the PDF of the issue, page 19
Letters¶
IF-THEN-ELSE (Education Vector, April 1991, p.27)
A slight modification to allow the simpler construct, IF-THEN without the ELSE to operate if that was desired:
∇ R←A ELSE B
[1] ⍝---FL1: IF <APL chrstr> THEN <APL chrstr>
ELSE <APL chrstr> construct
[2] M←(⍴A←,A)⌈⍴B←,B ⋄ R←(2,M)⍴(M↑A),M↑B
∇
∇ IF S
[1] ⍝---FL1: IF <APL chrstr> THEN <APL chrstr>
ELSE <APL chrstr> construct
[2] ⍎S
∇
∇R←C THEN A
[1] ⍝---FL1: IF <APL chrstr> THEN <APL chrstr>
ELSE <APL chrstr> construct
[2] ⍎(~¯1+⍴⍴A)/'→0,0⍴R←(⍎C)/A' ⋄ R←A[1+~⍎C;]
∇
I write APL code entirely without interaction with any humans, relying heavily on VECTOR, SIGAPL and the like for guidance. If you can recommend a good screen data input facility, I’d sure like to hear about it. I have written four or five for specialized use myself and have looked at several packages and bought one of them. I do not wish to have my workspaces prostituted with all kinds of objects about which I know little and which are named to conventions different from my own. I want a single object, perhaps written in C, which can be invoked on a setup basis (giving it a map of the screen together with a table of fields and attributes) and then called to manage screen input, allowing functions of my own to be executed (optionally) upon leaving any field. I want the data to be automatically sent from the screen to be scrollable or pageable up and down as I need that. And I want function-key-callable dialog boxes and information messages to pop up as needed. I know there are products which meet some or all of these requirements. If you know of any which you can recommend, I’d appreciate it.
(Editor’s comment: Any suggestions will be forwarded. If they are of general interest, they will be published.)