mirror of
https://git.sr.ht/~crc_/retroforth
synced 2024-11-16 19:48:56 +01:00
52 lines
1.2 KiB
Text
52 lines
1.2 KiB
Text
A pangram is a sentence that uses all the letters in the alphabet.
|
|
|
|
This is one way to determine if a sentence is a pangram using RETRO.
|
|
|
|
First, define a string containing the alphabet:
|
|
|
|
~~~
|
|
'abcdefghijklmnopqrstuvwxyz 'FULL s:const
|
|
~~~
|
|
|
|
Then a blank string of the same length for the test data:
|
|
|
|
~~~
|
|
'__________________________ 'TEST s:const
|
|
~~~
|
|
|
|
Now a word to do the actual test.
|
|
|
|
~~~
|
|
:s:pangram? (s-f)
|
|
'__________________________ &TEST #26 copy
|
|
s:to-lower [ c:letter? ] s:filter
|
|
[ dup $a - &TEST + store ] s:for-each
|
|
&TEST &FULL s:eq? ;
|
|
~~~
|
|
|
|
Breaking this down, the first line:
|
|
|
|
'__________________________ &TEST #26 copy
|
|
|
|
Copies a blank string over the TEST string. Then:
|
|
|
|
s:to-lower [ c:letter? ] s:filter
|
|
|
|
Converts the string to lowercase and strips out anything that's not a
|
|
letter. Then a quick iteration over each character:
|
|
|
|
[ dup $a - &TEST + store ] s:for-each
|
|
|
|
Reduces the letter to an index into the TEST string and stores the
|
|
letter at the appropriate spot. And finally:
|
|
|
|
&TEST &FULL s:eq? ;
|
|
|
|
Just compares the TEST and FULL strings to get the result.
|
|
|
|
Here's a couple of test cases:
|
|
|
|
~~~
|
|
'Hello_world! s:pangram?
|
|
'The_quick_brown_fox_jumped_over_the_lazy_dogs. s:pangram?
|
|
~~~
|