Task[edit]
Find the index of a string (needle) in an indexable, ordered collection of strings (haystack).

Raise an exception if the needle is missing.

If there is more than one occurrence then return the smallest index to the needle.

Extra credit
Return the largest index to a needle that has multiple occurrences in the haystack.

See also
 Search a list of records

To run:
Start up.
Make an example haystack.
Find "b" in the example haystack giving a count.
Destroy the example haystack.
Write "The index of ""b"" is " then the count on the console.
Wait for the escape key.
Shut down.
 
A needle is a string.
 
Some hay is some strings.
 
A bale is a thing with some hay.
 
A haystack is some bales.
 
To add some hay to a haystack:
Allocate memory for a bale.
Put the hay into the bale's hay.
Append the bale to the haystack.
 
To make an example haystack:
Add "a" to the example haystack.
Add "a" to the example haystack.
Add "b" to the example haystack.
Add "c" to the example haystack.
Add "d" to the example haystack.
 
\ As Plain English doesn't have exceptions, return -1 if the needle is not found.
To find a needle in a haystack giving a count:
Get a bale from the haystack.
Loop.
If the bale is nil, put -1 into the count; exit.
If the bale's hay is the needle, exit.
Put the bale's next into the bale.
Bump the count.
Repeat.