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Transforms
==========
Consider: character sequence to string fusing in PEG writer.
Consider: expression enumeration, to determine if there are common
expressions in the grammar which could be factored into
their own match procedures (*).
Consider: Transformations which expand the number of common
expressions. Example would be strings, i.e. macthing of
character sequences. Instead of matching all in one use a
nested sequence of matching ever-growing prefixes. This
ensures that common prefixes in terminal strings are
factored into one matcher. And if we use nonterminal
procedures (See * below) this also enhances the caching,
especially if common prefixes occur in different branches of
a choice.
(*) This could simple procedures, i.e. _not_ nonterminals. This would
be without caching. Could also be nonterminal procedures, with mode
expand (for value, discard would stay), to make its presence invisible
to the AS tree structure.
Removal of nonterminal chains
A <- B
B <- C
C <- ...
Static match results !!
mewriter has to be able to work with and
without static match. Basic expr modes are
something mewriter should do on its own
as well.
Compile *, + with helper nonterminals which are not shown as such
(mode: expand).
static match result - sequence - ability to remove checks after an
always ok call, and abort sequence upon always fail.
static match result - choice - ability to abort choice after ok, or
skip always fail branches.
Main parse routine can be simplified if start expression is a single
nonterminal, and not a real complex expression.
Need encoder for printable tcl char string.
- The basic encoder generates a string acceptable to tcl parser for
use in a script, as part of the code.
- The new encoder has to generate a string acceptable to the tcl
parser, for use in a script, which then written (puts) generates a
human readable representation of the character.
I.e. LF in basic encode is \n, when printed it is an invislble
character, i.e. a linefeed. In string/human encode it is \\n, which
prints as \n, making it a readable representation of the character
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