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Readline interface: Difference between revisions

Readline interface (view source)

Revision as of 23:26, 25 April 2016

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<br>The HELP (?), REDO, error checking, and abbreviations took up most of the program.
<br>"User" commands (subroutines) are identified with a leading period (.) to make it easier to understand what's what.
<lang rexx>/*REXX program to implementimplements a simple "readline" shell. (modeled after a DOS shell). */
trace off /*suppress echoing of non-zero RCretCodes*/
signal on syntax; signal on novaluenoValue /*handle REXX program errors. */
cmdX='ATTRIB CAL CHDIR COPY DEL DIR ECHO EDIT FC FIND KEDIT LLL MEM MKDIR MORE REM REXX',
'MEM MKDIR MORE REM REXX 'RMDIR SET TYPE VER XCOPY' /* ◄──── the legal/known commands. */
cls= 'CLS' /*define the pgmprogram to clear screen. */
@hist.= '*** command not defined. ***' /*initialize the history database. */
hist#=0 /*the number of commands in history.the history*/
prompt='Enter command ──or── ? ──or── Quit' /*the default PROMPT msg message text. */
sw=linesize() /*some REXX don't have this BIF. */
cls /*start with a clean slate. (terminal). */
redoing=0 /*flag for executing naked ReDO cmd. */
/* [↓] do it 'til the fat lady sings. */
do forever; if prompter() then iterate /*Nothing entered? Then go try again. */
select /* [↓] now then, let's rock n' roll. */
when wordpos(xxxF,cmdX)\==0 then call .cmdX
when xxxF=='EXIT' | xxxF="QUIT" then leave /*da fat lady is done singing*/
when xxxF=='HISTORY' then call .history
when xxxF=='HELP' then call .help
when xxxF=='PROMPT' then call .prompt
when xxxF=='REDO' then call .redo
otherwise call er 'unknown command:' xxx yyy
end /*select*/
end /*forever*/
 
say xxxF'ting···' do forever /*dosay itgoodbye, until'cause theit's fatpolite ladyto sings.do*/
exit if prompter() then iterate /*Nothingstick entered?a fork Soin tryit, again we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
select /*now then, let's rock & roll. */
er: say; say; say '****error****'; say; say arg(1); say; say; return
when wordpos(xxxF,cmdX)\==0 then call .cmdX
.prompt: if yyyU\=='' then prompt=yyy; return
when xxxF=='EXIT' | xxxF="QUIT" then leave /*the fat lady sung.*/
.cmdX: xxxF yyy; return
when xxxF=='HISTORY' then call .history
/*──────────────────────────────────────────────────────────────────────────────────────*/
when xxxF=='HELP' then call .help
err: say; say; say center(' error! ', max(40, linesize()%2), "*"); say
when xxxF=='PROMPT' then call .prompt
when xxxF=='REDO' then call .redo do j=1 for arg(); say arg(j); say; end; say; exit 13
/*──────────────────────────────────────────────────────────────────────────────────────*/
otherwise call er 'unknown command:' xxx yyy
noValue: syntax: call err 'REXX program' condition('C') "error",,
end /*select*/
condition('D'),'REXX source statement (line' sigl"):",sourceline(sigl)
end /*forever*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
.help: cmdsH= 'ATTRIB CHDIR CLS COPY DEL DIR ECHO EDIT FC FIND MEM MKDIR MORE PRINT',
'REM RMDIR SET TREE TYPE VER XCOPY' /*these have their own help via /? */
 
cmds= '?|Help|MANual ATTRIButes CALendar CD|CHDIR|CHANGEDir COPY DELete|ERASE',
say xxxF'ting...' /*say goodbye, 'cause it's polite*/
'DELete|ERASE DIR ECHO EDIT FC|FILECOMPAre FIND HISTory Kedit LLL',
exit /*stick a fork in it, we're done.*/
'MEM MD|MKDIR|MAKEDir MORE PRINT PROMPT Quit|EXIT',
/*───────────────────────────────error handling subroutines and others.─*/
'R4 RD|RMDIR|REMOVEDir REGINA REMark Rexx REDO SET TREE Type VER'
er: say; say; say '****error!****'; say; say arg(1); say; say; return
err: say; say; say center(' error! ',max(40,linesize()%2),"*"); say
do j=1 for arg(); say arg(j); say; end; say; exit 13
 
say center(strip(xxx yyy),sw-1,'═'); cmds_=cmds; yyyF=unabbrev(yyy)
novalue: syntax: call err 'REXX program' condition('C') "error",,
condition('D'),'REXX source statement (line' sigl"):",,
sourceline(sigl)
/*──────────────────────────────────.CMDX subroutine────────────────────*/
.cmdX: xxxF yyy; return
/*──────────────────────────────────.HELP subroutine────────────────────*/
.help: cmdsH='ATTRIB CHDIR CLS COPY DEL DIR ECHO EDIT FC FIND MEM',
'MKDIR MORE PRINT REM RMDIR SET TREE TYPE VER XCOPY'
/*the above commands have their own help via /? */
 
help. = 'No help is available for the' yyy "command."
cmds='?|Help|MANual ATTRIButes CALendar CD|CHDIR|CHANGEDir COPY DELete|ERASE',
help.cal = 'shows a calendar for the current month or specified month.'
'DELete|ERASE DIR ECHO EDIT FC|FILECOMPAre FIND HISTory Kedit LLL',
help.kedit = 'KEDITs the file specified.'
'MEM MD|MKDIR|MAKEDir MORE PRINT PROMPT Quit|EXIT',
help.lll = 'shows a formatted listing of files in the current directory.'
'R4 RD|RMDIR|REMOVEDir REGINA REMark Rexx REDO SET TREE Type VER'
help.prompt= 'sets the PROMPT message to the specified text.'
help.quit = 'quits (exits) this program.'
help.redo = 're-does the command # specified (or the last command).'
help.rexx = 'executes the REXX program specified.'
 
if yyy=='' then do j=1 while cmds_\==''
say center(strip(xxx yyy),sw-1,'═'); cmds_=cmds; yyyF=unabbrev(yyy)
parse var cmds_ x cmds_
say left('',sw%2) changestr('|',x," | ")
end /*j*/
else select
when wordpos(yyyF,cmdsH)\==0 then yyyF '/?'
otherwise cmd?=yyyF
if left(help.yyyF,1)\==' ' then say yyyF ' ' help.yyyF
else say help.yyyF
end /*select*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
.history: say center('history', sw-1, '═'); w=length(hist#)
do j=1 for hist#; say right(j,w) '═══►' @hist.j; end /*j*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
prompter: if redoing then do; redoing=0; z=hist#-1 /*special case, bare REDO. */
parse var @hist.z xxx yyy
end
else do; if prompt\=='' then do; say; say prompt; end
parse pull xxx yyy
end
 
xxxU=xxx; upper xxxU; if xxx=='' then return 1 /*No input? Then try again*/
help. = ' No help is available for the' yyy "command."
yyyU=yyy; upper yyyU; yyyU=strip(yyyU)
help.cal = 'shows a calendar for the current month or specified month.'
hist#=hist#+1; /*bump the history counter.*/
help.kedit = 'KEDITs the file specified.'
@hist.hist#=strip(xxx yyy) /*assign to history. */
help.lll = 'shows a formatted listing of files in the current directory.'
xxxF=unAbbrev(xxx) /*maybe expand abbreviation*/
help.prompt= 'sets the PROMPT message to the specified text.'
return 0
help.quit = 'quits (exits) this program.'
/*──────────────────────────────────────────────────────────────────────────────────────*/
help.redo = 're-does the command # specified (or the last command).'
.redo: select
help.rexx = 'executes the REXX program specified.'
when yyyU=='' then redoing=1 /*assume they want the last cmd. */
 
when words(yyy)\==1 then call er 'too many args specified for' xxx
if yyy=='' then do j=1 while cmds_\==''
when \datatype(yyy,'W') then call parseer var"2nd cmds_arg xisn't cmds_numeric for" xxx
otherwise say left('',sw%2) changestr('|',x," | ") nop
end /*jselect*/
if redoing then return /*handle with kid gloves. */
else select
yyy=yyy/1 /*normalize it: +7 7. 1e1 007 7.0*/
when wordpos(yyyF,cmdsH)\==0 then yyyF '/?'
say 'Re-doing:' otherwise cmd?=yyyF@hist.yyy
@hist.yyy
if left(help.yyyF,1)\==' ' then say yyyF ' ' help.yyyF
return
else say help.yyyF
/*──────────────────────────────────────────────────────────────────────────────────────*/
end /*select*/
return
/*──────────────────────────────────.HISTORY subroutine─────────────────*/
.history: say center('history',sw-1,'═'); w=length(hist#)
do j=1 for hist#
say right(j,w) '===>' @hist.j
end /*j*/
return
/*──────────────────────────────────.PROMPT subroutine──────────────────*/
.prompt: if yyyU\=='' then prompt=yyy; return
/*──────────────────────────────────PROMPTER subroutine─────────────────*/
prompter: if redoing then do /*special case for naked REDO */
redoing=0; z=hist#-1
parse var @hist.z xxx yyy
end
else do
if prompt\=='' then do; say; say prompt; end
parse pull xxx yyy
end
 
xxxU=xxx; upper xxxU; if xxx=='' then return 1 /*No input? Try again*/
yyyU=yyy; upper yyyU; yyyU=strip(yyyU)
hist#=hist#+1; /*bump the history counter. */
@hist.hist#=strip(xxx yyy) /*assign to history. */
xxxF=unAbbrev(xxx) /*expand the abbreviation (maybe)*/
return 0
/*──────────────────────────────────.redo subroutine────────────────────*/
.redo:
select
when yyyU=='' then redoing=1 /*assume they want the last cmd. */
when words(yyy)\==1 then call er 'too many args specified for' xxx
when \datatype(yyy,'W') then call er "2nd arg isn't numeric for" xxx
otherwise nop
end /*select*/
if redoing then return /*handle with kid gloves. */
yyy=yyy/1 /*normalize it: +7 7. 1e1 007 7.0*/
say 'Re-doing:' @hist.yyy
@hist.yyy
return
/*──────────────────────────────────UNABBREV subroutine─────────────────*/
unabbrev: procedure; arg ccc
select
when abbrev('ATTRIBUTES' , ccc, 6) then return 'ATTRIB'
when abbrev('CALENDAR',ccc,3) when abbrev('CALENDAR' , ccc, 3) then return 'CAL'
when abbrev('CHANGEDIR' , ccc, 7) |,
ccc=='CHDIR' |,
ccc=='CD' ccc=='CD' then return 'CHDIR'
when abbrev('CLEARSCREEN', ccc, 5) then return 'CLS'
when abbrev('FILECOMPARE', ccc, 9) then return 'FC'
when abbrev('DELETE' , ccc, 3) |,
ccc=='ERASE' ccc=='ERASE' then return 'DEL'
when abbrev('HISTORY',ccc,4) when abbrev('HISTORY' , ccc, 4) then return 'HISTORY'
when abbrev('HELP' , ccc, 1) |,
abbrev('MANUAL' , ccc, 3) |,
ccc=='?' ccc=='?' then return 'HELP'
when abbrev('MAKEDIR' , ccc, 5) |,
ccc=='MKDIR' |,
ccc=='MD' ccc=='MD' then return 'MKDIR'
when abbrev('KEDIT',ccc,1) when abbrev('KEDIT' , ccc, 1) then return 'KEDIT'
when abbrev('QUIT',ccc,1) when abbrev('QUIT' , ccc, 1) then return 'QUIT'
when abbrev('REMARK',ccc,3) when abbrev('REMARK' , ccc, 3) then return 'REM'
when abbrev('REMOVEDIR' , ccc, 7) |,
ccc=='RMDIR' |,
ccc=='RD' ccc=='RD' then return 'RMDIR'
when abbrev('REXX',ccc,1) when abbrev('REXX' , ccc, 1) then return 'REXX'
when abbrev('TYPE',ccc,1) when abbrev('TYPE' , ccc, 1) then return 'TYPE'
otherwise nop
end /*select*/
return ccc</lang>
</lang>
This REXX program makes use of &nbsp; '''LINESIZE''' &nbsp; REXX program (or BIF) which is used to determine the screen width (or linesize) of the terminal (console).
<br>The &nbsp; '''LINESIZE.REX''' &nbsp; REXX program is included here &nbsp; ──► &nbsp; [[LINESIZE.REX]].<br>
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