User Commands (UCMDs) in Dyalog APL

1. User Commands (UCMDs) in Dyalog APL Dan Baronet A programmer's tool V1.04

2. Agenda This tutorial is divided into 4 steps: • Why UCMDs • Dyalog's UCMDs • Implementation of the UCMD framework • Your UCMDs: how to write them

3. Why The idea is to provide a mechanism for accessing tools anywhere by • separating utilities from the workspace • make them available at any time

4. History The concept of user commands (UCMDs) is not new. APL/PC had them in the 90s. Their implementation was different but the idea was the same

5. User Commands A user command (UCMD) is similar to a system command like )LOAD or)WSID. It is a call to an independent routine written by a user, not a routine provided by the system. It can be used anytime.

6. User Commands System commands start with a ), e.g. )SAVE User commands start with a ], e.g. ]WSLOC

7. User Commands - syntax Like their system commands counterpart, user commands may take arguments, e.g. )WSID [newname] And ]FNSLIKE [pattern] Just like system commands they are not case sensitive.

8. User Commands - syntax Unlike system commands, in the actual implementation, they can also take modifiers, e.g. ]FNSLIKE [Pattern] –format Modifiers are preceded by a specific character (here –) Modifiers ARE case sensitive.

9. User Commands - syntax This is Dyalog's implementation. UCMDs could take any format. WE decide what is acceptable.

10. User Commands - syntax UCMDs are based on SALT.

11. SALT • SALT is basically a pair of programs to write and read Unicode text files • UCMDs make use of these 2 functions to write out and read back their code • SALT has many other features that are irrelevant with UCMDs (but nonetheless useful) Dyalog’11 - Boston

12. SALT • When an object is saved using SALT it is tagged • That tag is used afterwards when resaving the object, e.g. after editing it • That tag remains with the object unless removed, even when the workspace is saved Dyalog’11 - Boston

13. User Commands Dyalog comes pre-packaged with a set of user commands divided into groups. Groups exist for SALT, workspace utilities, code utilities, user commands management, etc.

14. User Commands For example the command ]SAVE , which saves an OBJECT (not a workspace), takes up to 2 arguments, saving the object named in the 1st argument to, if present, the location named in the 2nd argument. Ex: ]savemyfn \my\location\myfn To bring the object back use the command ]LOAD: ]load my\location\myfn

15. User Commands - Help General help can be obtained with ]?? Or ]help The list of all commands can be obtained with ]? And ]?+ Specific help for a command can be obtained with ]?cmdx Or more detailed help, if any, with ]??cmdx Or ]?\path\to\file\containing\a\user\cmd

16. User Commands available Dyalog comes pre-packaged with some already defined UCMDs They are divided into groups: • SALT Samples • Spice (UCMD) svn • Sysmon System • Tools Transfer • wsutils

17. Group SALT These are the same as their SALT functions: • Save object [tolocation] • Load location • Compare file1 [file2] • Settings [type [value]] • List [folder] • Snap tolocation • Removeversions file

18. Group Spice These are commands used to manage the User commands system: • Uload command • Udebug [ON|OFF] • Uclean • Unew [name] • Ureset • Uupdate [SALT] • Uversion [wsname] • Umonitor

19. Group svn This group contains commands to mimic SubVersion's commands: • svnci: commit changes • Svnco: check out • Svnadd/delete: add/delete new files • Svnstatus/resolve • Svndiff: show changes to a file • Svnimport/export • Svnupdate: bring in most recent changes

20. Group SysMon This group is used to monitor the system: • APLMON: used to monitor expressions by primitive, ex: ]aplmon {+/1=⍵∨⍳⍵}¨⍳1000 –file=\tmp\data • CPUtime: used to find CPU used for expressions, ex: ]cputime {+/1=⍵∨⍳⍵}¨⍳1000 • Monitor: used to find lines consuming the most CPU • Profile: used to profile an application

21. Group Transfer This group is used to move code in and out of ATF files with • in/out And move code in and out of "extended" files with code translation with • inx/outx

22. Groups Tools & WSutils These 2 groups contain various utilities e.g. to show a subset of names following a specific pattern or do function call analysis or search the workspace for strings of code/text: ]fnslike GUI* -date=>20090307 ]fncalls MainProgram -details -treeview ]wsloc abc -exclude=ct -recursive

23. UCMDs - implementation • The code to run a UCMD is contained in a class or namespace in a SALT (text, Unicode)file. • That file may be host to several UCMDs • Command names are case insensitive, e.g. ‘find’ and ‘FIND’ call the same code • Switches names are case sensitive • UCMDs are grouped together, e.g. utilities can be grouped under the group ‘wsutils’ • The class or namespace must contain at least 3 public functions: ‘List’, ‘Run’ and ‘Help’

24. UCMDs - implementation • The ‘List’ function is used to gather basic info displayed when using ]?+ • The ‘Help’ function is used to display more complete info when using ]?cmdx or ]??cmdx • The ‘Run’ function is the one doing the work.

25. UCMDs - implementation The whole framework is based on 2 things: • SALT: used to read/write Unicode text files • Spice: used to implement the rules of UCMDs

26. UCMDs – an example Let’s assume we have a simple function we wish to call once in a while without having to copy/call/erase it each time: calendar 3 March S M T W T F S 1 2 3 4 5 6 7 8 9 10 11 12 12 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

27. UCMDs – an example Let’s create a user command named CAL that we will call with a single argument like this: ]cal 3

28. UCMDs – an example We need to create a class with the 3 basic functions, the <List> function: :Namespace dates ⎕IO←1 ⋄ ⎕ML←1 ∇ r←List r←⎕NS ⍬ ⍝ Name, group, short description and parsing rules r.Name← 'cal' r.Group←'dates' r.Desc← 'returns the calendar for a given month' r.Parse←'' ∇

29. UCMDs – an example The HELP function: ∇ r←Help dummy r←'Enter a month as argument' ∇

30. UCMDs – an example The RUN function: ∇ r←Run(a1 a2) 'calendar' ⎕CY 'myutils' r←calendar ⍎a2 ∇ :endnamespace

31. UCMDs – an example Because each class may contain more than one UCMD the HELP and RUN functions should really account for that.

32. UCMDs – an example HELP function for more than one command: ∇ r←HelpCmd :Select Cmd :Case 'cal' r← 'Enter a month as argument' :Case 'other' … :EndSelect ∇

33. UCMDs – an example The RUN function for more than one command: ∇ r←Run(CmdArgs) :Select Cmd :Case 'cal' 'calendar' ⎕CY 'myutils' r←calendar ⍎Args :Case 'other' … :EndSelect ∇

34. UCMDs – Parsing If automatic parsing of the arguments is desired the system will look at the line given as argument, split the tokens on spaces and put the resulting vector of text vectors in variable 'Arguments’ in a namespace. That namespace will be given as the 2nd argument to the function <Run>. To request parsing simply put in 'Parse' (in function <List>) the rules to follow, e.g. '3' to ensure 3 arguments. If no parsing is desired simply leave 'Parse' empty.

35. UCMDs – Parsing • If we wish the system to check the number of arguments (here 1) for us we say it in <List>: ∇ r←List :Access Shared Public r←⎕NS¨1⍴⊂⍬ ⍝ Name, group, short description and parsing rules r.Name← ⊂ 'cal' r.Group←⊂ 'dates' r.Desc← ⊂ 'returns the calendar for a given month' r.Parse← '1' ∇ In that case the 2nd argument of <Run> will contain a namespace but only AFTER the framework has ensured only ONE argument has been supplied.

36. UCMDs – Parsing ∇ r←Run(Cmda2) :Select Cmd :Case 'cal' 'calendar' ⎕CY 'myutils' r←calendar ⍎1⊃a2.Arguments :EndSelect ∇ Function <calendar> can also/should be defined in the class instead of being copied in.

37. UCMDs – an example. ]cal 3 March S M T W T F S 1 2 3 4 5 6 7 8 9 10 11 12 12 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

38. UCMDs – an example If Parsing is enabled, entering the wrong number of arguments will be refused: ]cal Command Execution Failed: too few arguments ]cal 2 3 Command Execution Failed: too many arguments

39. UCMDs location The location of user commands is preset to Dyalog's folder SALT\spice under APL's location, e.g. C:\program files\Dyalog\V121\SALT\spice

40. UCMDs location The location of UCMDs is one of SALT's settings. To know what they are: []SE.SALT.Settings 'cmddir' Or, as a UCMD: ]settings cmddir

41. UCMDs location You can reset it too. It follows the same rule as SALT's workdir setting, i.e. it is a series of paths separated by semicolons, e.g. \my\own\path;C:\program files\Dyalog\V121\SALT\Spice For example, to add "\my\own\path" to the existing path: (note the comma) ]settings cmddir,\my\own\path

42. UCMDs location You can set them manually or in Options/Configure…

43. UCMDs location

44. UCMDs location Some commands are always there: Spice's and SALT's Doing (note NO comma) ]settings cmddir \my\own\path Will keep Spice and SALT's commands even though they have not been specified.

45. UCMDs – Advanced Topics Debugging code ]udebug ON|OFF When debugging is OFF errors are reported in the calling environment: Command Execution Failed: DOMAIN ERROR When debugging is ON errors are reported in the class: DOMAIN ERROR calendar[4] r←n÷month ∧

46. UCMDs – Advanced Topics Switches Those can be specified in the Parse variable: They come in different forms: • Without a value: /sw • With a value: /sw= • Possibly with a value: /sw[=] The specification for each includes the (same) switch delimiter (here /)

47. UCMDs – Advanced Topics Switches A set of possible values may be specified, e.g. /animal=cat monkey giraffe A set of possible characters can also be specified: /vowel ∊ aeiou Or /vowel [∊] aeiou If the switch can be specified without a value

48. UCMDs – Advanced Topics Switches – Examples 1. Switch time takes a value, switch PM does not, switch delimiter is /: Parse ← '/time= /PM' 2. Switch Primemay accept values 2, 3, 5 and 7, switch Octal accepts values made out of '01234567', delimiter is +: Parse ←'+Prime[=]2 3 5 7 +Octal∊01234567'

49. UCMDs – Advanced Topics Switches – Examples Switches and number of arguments are specified together. A command accepting 2 arguments and a switch-offset with a value would be specified as: Parse ←'2 -offset='

50. UCMDs – Advanced Topics Arguments Arguments are delimited by spaces. If an argument must contain spaces, or the switch delimiter character or a quote, it should be surrounded by quotes. For example, if the switch delimiter is /, the following call will contain 4 arguments: ]mycmd'arg 1' '2001/4/5' OK "I'm" /lights=on