(patch for Bash) try-block and exception

[William Park]

(crossposted to comp.lang.python, because this may be of interest to
them.)

Python has try-block, within which you can raise exception. Once it's
raised, execution breaks out of the try-block and is caught at the end
of try-block.

Now, Bash has similiar feature. I've added try-block and 'raise'
builtin into Bash-3.0. Typical usage would go something like
try
echo a
raise
echo b
done
or
try
echo a
raise 2
echo b
done in
0) echo okey ;;
1) echo raised 1 ;;
2) echo raised 2 ;;
*) echo really bad ;;
esac

The exception is positive integer and is raised by 'raise' builtin, just
like 'break' for the for/while/until loops. And, it can be caught by
using optional case-like statement.

Ref:
http://freshmeat.net/projects/bashdiff/
help try
help raise

 

[William Park]

(crossposted to comp.lang.python, because this may be of interest to
them.)

Python has try-block, within which you can raise exception. Once it's
raised, execution breaks out of the try-block and is caught at the end
of try-block.

Now, Bash has similiar feature. I've added try-block and 'raise'
builtin into Bash-3.0. Typical usage would go something like
try
echo a
raise
echo b
done
or
try
echo a
raise 2
echo b
done in
0) echo okey ;;
1) echo raised 1 ;;
2) echo raised 2 ;;
*) echo really bad ;;
esac

Typo... I pasted an old example. No globbing or any shell expansion is
done.
try
echo a
raise 2
echo b
done in
0) echo okey ;;
1) echo raised 1 ;;
2) echo raised 2 ;;
esac

 

[Harry Putnam]

This link doesn't appear to lead to a `download' option..

 

[William Park]

This link doesn't appear to lead to a `download' option..

It's two step dance.
first, http://freshmeat.net/projects/bashdiff/
then, http://home.eol.ca/~parkw/index.html#bash (homepage)
then, http://home.eol.ca/~parkw/bash.diff

Next feature I'll tackle is list comprehension.

 

[Kenny McCormack]

Next feature I'll tackle is list comprehension.

Are you saying that you don't understand how lists work?
If so, post an item here - I'm sure people will be more than willing to help.

 

[Greg Ewing]

try
echo a
raise 2
echo b
done in
0) echo okey ;;
1) echo raised 1 ;;
2) echo raised 2 ;;
*) echo really bad ;;
esac

try...done...esac? What a delightfully eclectic combination
of syntax.

Why doesn't it end with 'yrt'?

 

[William Park]

try...done...esac? What a delightfully eclectic combination
of syntax.

Why doesn't it end with 'yrt'?

'try-done' was chosen because it resembles while-loop where you would
break out of; and, '-in-esac' was chosen because it resembles case
statement. Also, I didn't want to introduce too many new keywords.