38 lines
3.1 KiB
Rexx
38 lines
3.1 KiB
Rexx
/*REXX program displays a list, then prompts the user for a selection number (integer).*/
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do forever /*keep prompting until response is OK. */
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call list_create /*create the list from scratch. */
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call list_show /*display (show) the list to the user.*/
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if #==0 then return '' /*if list is empty, then return null.*/
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say right(' choose an item by entering a number from 1 ───►' #, 70, '═')
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parse pull x /*get the user's choice (if any). */
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select
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when x='' then call sayErr "a choice wasn't entered"
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when words(x)\==1 then call sayErr 'too many choices entered:'
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when \datatype(x,'N') then call sayErr "the choice isn't numeric:"
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when \datatype(x,'W') then call sayErr "the choice isn't an integer:"
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when x<1 | x># then call sayErr "the choice isn't within range:"
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otherwise leave /*this leaves the DO FOREVER loop.*/
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end /*select*/
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end /*forever*/
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/*user might've entered 2. or 003 */
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x=x/1 /*normalize the number (maybe). */
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say; say 'you chose item' x": " #.x
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return #.x /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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list_create: #.1= 'fee fie' /*this is one method for list-building.*/
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#.2= 'huff and puff'
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#.3= 'mirror mirror'
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#.4= 'tick tock'
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#=4 /*store the number of choices in # */
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return /*(above) is just one convention. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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list_show: say /*display a blank line. */
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do j=1 for # /*display the list of choices. */
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say '[item' j"] " #.j /*display item number with its choice. */
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end /*j*/
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say /*display another blank line. */
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return
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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sayErr: say; say '***error***' arg(1) x; say; return
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