Make note of two more input handling / memory management options.

Also, update the ASDL line count.

osh/lex.py

@@ -40,6 +40,39 @@

http://re2c.org/examples/example_03.html

UPDATE: Two More Options
------------------------

3. Change the \n at the end of every line to \0.  \0 becomes Id.Op_Newline, at
least in lex_mode.OUTER.

Advantage: This makes the regular expressions easier to generate, but allows
you to read in the whole file at once instead of allocating lines.

Disadvantages:
- You can't mmap() the file because the data is mutated.  Or it will have to be
  copy-on-write.
- You can't get rid of comment lines if you read the whole file.

4. Read a line at a time.  Throw away the lines, unless you're parsing a
function, which should be obvious.

After you parse the function, you can COPY all the tokens to another location.
Very few tokens need their actual text data.  Most of them can just be
identified by ID.

Contents are relevant:

- Lit_Chars, Lit_Other, Lit_EscapedChar, Lit_Digits
- Id.Lit_VarLike -- for the name, and for = vs +=
- Id.Lit_ArithVarLike
- VSub_Name, VSub_Number
- Id.Redir_* for the LHS file descriptor.  Although this is one or two bytes
  that could be copied.

You can also take this opportunity to enter the strings in an intern table.
How much memory would that save?

Remaining constructs
--------------------

scripts/count.sh

@@ -41,7 +41,7 @@ all() {
  echo

  echo 'ASDL'
  wc -l asdl/{asdl_,py_meta,encode,format}.py | sort --numeric
  wc -l asdl/{asdl_*,const,py_meta,encode,format}.py | sort --numeric
  echo

  echo 'CODE GENERATORS'