User defined pipe and redirection operators: Difference between revisions

Content added Content deleted
m (create "user defined" the equivalents of the Unix shell "<", "|", ">", "<<" and ">>" operators.)
m (augment the sample/example shell script)
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'''Task:'''
'''Task:'''
If the language supports operator definition, then:
If the language supports operator definition, then:
* create "user defined" the equivalents of the Unix shell "<", "|", ">", "<<" and ">>" operators.
* create "user defined" the equivalents of the Unix shell "<", "|", ">", "<<", ">>" and $(cmd) operators.
* Provide simple equivalents of: cat, tee, grep, uniq, wc, head & tail, but as procedures native to the specific language.
* Provide simple equivalents of: cat, tee, grep, uniq, wc, head & tail, but as procedures native to the specific language.
* Replicate the below sample shell script, but in the specific language.
* Replicate the below sample shell script, but in the specific language.
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'''Sample shell script:''' ''¢ draft - pending a better (more interesting) suggestion ¢''
'''Sample shell script:''' ''¢ draft - pending a better (more interesting) suggestion ¢''
<lang sh>(
<lang sh>
aa="$(
⚫
head -4 < List_of_computer_scientists.lst
(
⚫
cat List_of_computer_scientists.lst | grep ALGOL | tee ALGOL_pioneers.lst
tail -4 List_of_computer_scientists.lst
head -4 < List_of_computer_scientists.lst;
⚫
cat List_of_computer_scientists.lst | grep ALGOL | tee ALGOL_pioneers.lst;
⚫
) | uniq | tee "the_important_scientists.lst" | grep aa</lang>
⚫
tail -4 List_of_computer_scientists.lst
⚫
) | sort | uniq | tee "the_important_scientists.lst" | grep aa
);
echo "Pioneer: $aa"
</lang>
'''Input File:'''
'''Input File:'''
* List_of_computer_scientists.lst - cut from wikipedia.
* List_of_computer_scientists.lst - cut from wikipedia.
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'''Output:'''
'''Output:'''
<pre>
<pre>
Adriaan van Wijngaarden - Dutch pioneer; ARRA, ALGOL
Pioneer: Adriaan van Wijngaarden - Dutch pioneer; ARRA, ALGOL
</pre>
</pre>
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