Keywords List
Whitespaces:
Delimeters:
Case
insensitive
Whole words match
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Description
This code generator produces the PIC assembler code to
look for keywords in a string or a serial ASCII stream.
Parsing routine receives one character at a time and
returns the keyword code, or the next state, or error
code. The keywords codes are given in the order they were
written, starting from 1.
You can specify whether keywords are matched as the whole
words or just starting unique part. This let's you use
shorthand names for the keywords. Also, case
insensitiveness can be specified.
The routine can skip whitespaces before a keyword. Enter
the desired characters in the form entry Whitespaces. In
some cases it's probably better to delete carriage return
(0x0d) or line feed (0x0a) characters if you don't need
them, or add some others. To detect the end of a keyword
the routine needs to know what characters separate
keywords in the text stream (form entry Delimiters).
Often, they are the same as whitespaces, but you might
want to add '\0' to work with zero terminated strings, or
'(' in case the keyword is a function name, e.g.
Speed(100). A delimiter character is received as a
look-ahead character after a keyword matched to make sure
that the keyword ended.
The routine is implemented as a variation of state machine,
without explicit tables. The routine is a relatively fast
runner, since it compares a character to a minimum number of
constant characters, just enough to disambiguate the text
meaning.
The size of the generated code is directly related to the
number of keywords and their length. It takes about four
instructions of program memory per each character in the
text area plus jump table and a couple of small routines.
See example
on how to
call the parsing routine.
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