Revision 3774
Added by Aaron Marcuse-Kubitza over 12 years ago
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#!/bin/bash |
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# Expands bash-style {} expressions.
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# See <http://www.gnu.org/software/bash/manual/bash.html#Brace-Expansion>. |
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# Usage: [env expand_braces_debug=1] self <in >out |
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# Filters each line from stdin to stdout. |
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# Warning: Due to shell limitations, a blank line will be interpreted as EOF. |
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echoEach () { local line; for line in "$@"; do echo "$line"; done; }
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replaceRecursive () |
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{
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local sedExpr="$1" str="$2" prevStr |
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while true; do |
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prevStr="$str" |
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str="$(echo "$str"|sed -e "$sedExpr")" |
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test "$str" = "$prevStr" && break # done if nothing replaced |
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done |
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echo "$str" |
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} |
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debug () |
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{
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local label="$1" str="$2" |
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test -n "$expand_braces_debug" && (echo "** $label:"; echo "$str") >&2 |
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} |
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singleQuote="'" |
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singleQuoteEsc="'\''" |
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CR=$'\r' |
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LF=$'\n' |
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braceKeep='./{'
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bracketKeep='{*[*,*]*}'
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nonBracket="[^][]*" # matches non-[] chars
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brackets="($nonBracket\[$nonBracket\])*$nonBracket"
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while true; do |
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read # get next line from stdin; strips trailing newlines |
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line="$REPLY" |
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test -z "$line" && break # EOF if no line or empty line |
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if test "${line/$braceKeep/}" != "$line" \
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-o "${line/$bracketKeep/}" != "$line"; then # line contains unparseable exprs
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echo "$line" # don't expand |
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else |
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line="${line//$CR/}" # remove \r
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line="${line//$singleQuote/$singleQuoteEsc}" # escape single quotes
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line="$(echo "$line"|sed -e "s/[^{,}]+/'&'/g")" # escape non-brace chars
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eval echoEach $line # brace-expand $line |
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fi |
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line="${line//$CR/}" # remove \r
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origLine="$line" |
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debug orig "$line" |
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line="${line//$singleQuote/$singleQuoteEsc}" # escape single quotes
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line="$(echo "$line"|sed -e "s/[^{,}]+/'&'/g")" # escape non-brace chars
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# Escape commas inside [], which should not be used for {}.
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# Note that '' around "," are closing and opening the escaped string, |
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# not the other way around. |
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line="$(replaceRecursive "s/(\[$nonBracket)','/\1,/g" "$line")" # innermost |
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# Also support one level of nesting, which is the most we currently use. |
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line="$(replaceRecursive "s/(\[$brackets)','/\1,/g" "$line")" # 1st outer |
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debug escaped "$line" |
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debug expanded |
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eval echoEach $line # brace-expand $line |
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done |
Also available in: Unified diff
expand_braces: Also expand XPaths containing [], with up to one level of nesting (which is the most we currently use), because many {} XPaths do in fact contain []. Debug-print intermediate values when env var expand_braces_debug is true. Added usage message.