Grammalecte  Check-in [0283fcb23c]

WRITING RULES FOR GRAMMALECTE

Note: This documentation is obsolete right now.

# Principles #

Grammalecte is a bi-passes grammar checker engine. On the first pass, the
engine checks the text paragraph by paragraph. On the second passe, the engine
check the text sentence by sentence.

The command to switch to the second pass is:
[++]




In each pass, you can write as many rules as you need.

A rule is defined by:
* [optional] flags “LCR” for the regex word boundaries and case sensitiveness
* a regex pattern trigger
* a list of actions (can’t be empty)

* [optional] user option name for activating/disactivating the rule
* [optional] rule name

There is no limit to the number of actions and the type of actions a rule can
launch. Each action has its own condition to be triggered.

There are three kind of actions:
- Error warning, with a message, and optionally suggestions, and optionally an URL
- Text transformation, modifying internally the checked text
- Disambigation action, setting tags on a position


The rules file for your language must be named “rules.grx”.

The settings file must be named “config.ini”.

All these files are simple utf-8 text file.
UTF-8 is mandatory.



# Rule syntax #

__LCR/option(rulename)__  pattern
    <<- condition ->> error_suggestions  # message_error|http://awebsite.net...
    <<- condition ~>> text_rewriting
    <<- condition =>> commands_for_disambigation
    ...

Patterns are written with the Python syntax for regular expressions:
http://docs.python.org/library/re.html

There can be one or several actions for each rule, executed the order they are
written.

Conditions are optional, i.e.:
    <<- ~>> replacement


LCR flags means:
* L: Left boundary for the regex
* C: Case sensitiveness
* R: Right boundary for the regex

Left boundary (L):
    `[`   word boundary
    `<`   no word boundary

right boundary (R):
    `]`   word boundary
    `>`   no word boundary

Case sensitiveness (C):
    `i`     case insensitive
    `s`     case sensitive
    `u`     uppercase allowed for lowercased characters
            i.e.:  "Word"  becomes  "W[oO][rR][dD]"

Examples:
    __[i]__  pattern
    __<s]__  pattern
    __[u>__  pattern
    __<s>__  pattern
    ...


User option activating/disactivating is possible with an option name placed
just after the LCR flags, i.e.:
    __[i]/option1__  pattern
    __[u]/option2__  pattern
    __[s>/option1__  pattern
    __<u>/option3__  pattern
    __<i>/option3__  pattern
    ...

Rules can be named:
    __[i]/option1(name1)__  pattern
    __[u]/option2(name2)__  pattern
    __[s>/option1(name3)__  pattern
    __<u>/option3(name4)__  pattern
    __<i>/option3(name5)__  pattern
    ...

Each rule name must be unique.


The LCR flags are also optional. If you don’t set these flags, the default LCR
flags will be:
    __[i]__

Example. Report “foo” in the text and suggest "bar":

    foo <<- ->> bar # Use bar instead of foo.

Example. Recognize and suggest missing hyphen and rewrite internally the text
with the hyphen:

    __[s]__ foo bar
        <<- ->> foo-bar # Missing hyphen.
        <<- ~>> foo-bar


== Simple-line or multi-line rules ==

Rules can be break to multiple lines by leading tabulators or spaces.
You should use 4 spaces.

Examples:

    __<s>__ pattern
        <<- condition ->> replacement
        # message
        <<- condition ->> suggestion # message
        <<- condition
        ~>> text_rewriting
        <<- =>> disambiguation

    __<s>__ pattern <<- condition ->> replacement # message


## Comments ##

Lines beginning with # are comments.






## End of file ##

With the command:

`#END`

at the beginning of a line, the compiler won’t go further.
Whatever is written after will be considered as comments.


## Whitespaces at the border of patterns or suggestions ##

Example. Recognize double or more spaces and suggests a single space:

    __<s>__  "  +" <<- ->> " " # Extra space(s).

ASCII " characters protect spaces in the pattern and in the replacement text.


## Pattern groups and back references ##

It is usually useful to retrieve parts of the matched pattern. We simply use
parenthesis in pattern to get groups with back references.

Example. Suggest a word with correct quotation marks:

\"(\w+)\" <<- ->> “\1” # Correct quotation marks.

Example. Suggest the missing space after the !, ? or . signs:

__<i]__ \b([?!.])([A-Z]+) <<- ->> \1 \2 # Missing space?

Example. Back reference in messages.

(fooo) bar <<- ->> foo bar # “\1” should be:


## Name definitions ##

Grammalecte supports name definitions to simplify the description of the
complex rules.

Example.

DEF: name pattern

Usage in the rules:

({name}) (\w+) ->> "\1-\2" # Missing hyphen?


## Multiple suggestions ##

Use | in the replacement text to add multiple suggestions:

Example 7. Foo, FOO, Bar and BAR suggestions for the input word "foo".

foo <<- ->> Foo|FOO|Bar|BAR # Did you mean:


## No suggestion ##

You can display message without making suggestions. For this purpose,
use a single character _ in the suggestion field.

Example. No suggestion.

foobar <<- ->> _ # Message


## Positioning ##

Positioning is valid only for error creation and text rewriting.

By default, the full pattern will be underlined with blue. You can shorten the
underlined text area by specifying a back reference group of the pattern.
Instead of writing ->>, write -n>>  n being the number of a back reference
group. Actually,  ->>  is similar to  -0>>

Example.

(ying) and yang <<- -1>> yin # Did you mean:
__[s]__ (Mr.) [A-Z]\w+ <<- ~1>> Mr

### Comparison ###

Rule A:
ying and yang       <<- ->>     yin and yang        # Did you mean:

Rule B:
(ying) and yang     <<- -1>>    yin                 # Did you mean:

With the rule A, the full pattern is underlined:
    ying and yang
    ^^^^^^^^^^^^^

With the rule B, only the first group is underlined:
    ying and yang
    ^^^^


## Longer explanations with URLs ##

Warning messages can contain optional URL for longer explanations separated by "|":

(your|her|our|their)['’]s
    <<- ->> \1s
    # Possessive pronoun:|http://en.wikipedia.org/wiki/Possessive_pronoun



# Text rewriting #

Example. Replacing a string by another

Mr. [A-Z]\w+ <<- ~>> Mister

WARNING: The replacing text must be shorter than the replaced text or have the
same length. Breaking this rule will misplace following error reports. You

You can also call Python expressions.

__[s]__ Mr. ([a-z]\w+) <<- ~1>> =\1.upper()



# Disambiguation #

When Grammalecte analyses a word with morph or morphex, before requesting the
POS tags to the dictionary, it checks if there is a stored marker for the
position where the word is. If there is a marker, Grammalecte uses the stored
data and don’t make request to the dictionary.

The disambigation commands store POS tags at the position of a word.

define(\1, "po:nom is:plur|po:adj is:sing|po:adv")

This will store a list of tags at the position of the first group:
["po:nom is:plur", "po:adj is:sing", "po:adv"]



# Conditions #

Conditions are Python expressions, they must return a value, which will be
evaluated as boolean. You can use the usual Python syntax and libraries.

You can call pattern subgroups via \0, \1, \2…

Example:
    
    these (\w+)
        <<- \1 == "man" -1>> men        # Man is a singular noun. Use the plural form:

You can also apply functions to subgroups like:
    \1.startswith("a")
    \3.islower()
    re.match("pattern", \2)
    …


## Standard functions ##

word(n)
    catches the nth next word after the pattern (separated only by white spaces).
    returns None if no word catched

word(-n)
    catches the nth next word before the pattern (separated only by white spaces).

option(option_name)
    returns True if option_name is activated else False

Note: the analysis is done on the preprocessed text.


## Default variables ##

sCountry

It contains the current country locale of the checked paragraph.

colour <<- sCountry == "US" ->> color # Use American English spelling.



# Expressions in the suggestions #

Suggestions (and warning messages) started by an equal sign are Python string expressions
extended with possible back references and named definitions:

Example:

foo\w+ ->> = '"' + \0.upper() + '"' # With uppercase letters and quoation marks