Changing words in text files using multiple dictionaries - bash

Question

I have a bunch of files which need to be translated using custom dictionaries. Each file contains a line indicating which dictionary to use. Here's an example:
*A:
!
=1
*>A_intro
1r
=2
1r
=3
1r
=4
1r
=5
2A:maj
*-
In the file above, *A: indicates to use dictA.
I can translate this part easily using the following syntax:
sed -f dictA < myfile
My problem is that some files require a change of dictionary half way in the text. For example:
*B:
1B:maj
2E:maj/5
2B:maj
2E:maj/5
*C:
2F:maj/5
2C:maj
2F:maj/5
2C:maj
*-
I would like to write a script to automate the translation process. Using this example, I would like the script to read the first line, select dictB, use dictB to translate each line until it reads *C:, select dictC, and then keep going.

Answer 1

Thanks #Cyrus. That was useful. Here's what I ended up doing.
#!/bin/sh
key="sedDictNull.txt"
while read -r line || [ -n "$line" ] ## Makes sure that the last line is read. See http://stackoverflow.com/questions/12916352/shell-script-read-missing-last-line
do
if [[ $line =~ ^\*[Aa]:$ ]]
then
key="sedDictA.txt"
elif [[ $line =~ ^\*[Aa]#:$ ]]
then
key="sedDictA#.txt"
fi
echo "$line" | sed -f $key
done < $1

Answer 2

I assume your "dictionaries" are really sed scripts that search and replace, like this:
s/2C/nothing/;
s/2B/something/;
You could reorganize these scripts into sections, like this:
/^\*B:/, /^\*[^B]/ {
s/1B/whatever/;
s/2B/something/;
}
/^\*C:/, /^\*[^C]/ {
s/2C/nothing/;
s/2B/something/;
}
And, of course, you could do that on the fly:
for dict in B C
do echo "/^\\*$dict:/, /^\\*[^$dict]/ {"
cat dict.$dict
echo "}"
done | sed -f- dict.in