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| -rw-r--r-- | ship/README.markdown | 22 | 
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| diff --git a/ship/README.markdown b/ship/README.markdown index 01a63bd6..9686d099 100644 --- a/ship/README.markdown +++ b/ship/README.markdown @@ -30,3 +30,25 @@    Undo `make install` with      make distclean + +## Macro Development + +  To define a new macro, you have to add a function like + +    ## usage: BRE -> FUNCTION_NAME \1 [\2 ...] + +  where `BRE` is a basic regular expression, that has to match a whole +  line.  `FUNCTION_NAME` should be the name of a function that outputs +  a `sed` script.  `\1` refers to the line number, where the macro is +  used and `\2 ...` are the backreferences into `BRE`.  E.g. + +    ## usage: #@date \([.*]\) -> build_datemacro \1 \2 +    build_datemacro() { +      printf '%da\\\n%s\n' "$1" "$(date +"$2")" +    } + +  Like in this example, the line number `\1`, which gets mapped to `$1`, +  is usually used to only change the line, where the macro got called. +  The second argument gets passed as format specifier to `date`. + +  Further examples can be found in `./build`. | 
