Icon+Unicon/Intro: Difference between revisions
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In SNOBOL an undefined value defaults to the null string "" and the null string is coerced into a zero 0 if needed for math. Thus the surprise output above is 2 and not 5 as expected. While on close inspection the error is apparent, you can see how this could be missed in a large program predominated by global variables. |
In SNOBOL an undefined value defaults to the null string "" and the null string is coerced into a zero 0 if needed for math. Thus the surprise output above is 2 and not 5 as expected. While on close inspection the error is apparent, you can see how this could be missed in a large program predominated by global variables. |
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In Icon/Unicon &null is not coerced and so: |
In Icon/Unicon &null is not coerced by operators and so: |
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<lang Icon> write( 2 + &null ) # run time error 101 |
<lang Icon> write( 2 + &null ) # run time error 101 |
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write( "abc" || &null ) # run time error 103 |
write( "abc" || &null ) # run time error 103 |
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