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Simple question about the lexer [message #1750314]

Mon, 19 December 2016 20:03

Eric Salemi

Messages: 35
Registered: September 2016
Location: Belgium

Member

The following DSL:

grammar com.septentrio.sandbox.flax.Flax with org.eclipse.xtext.common.Terminals
generate flax "http://www.septentrio.com/sandbox/flax/Flax"
Box:
    'label' name=QualifiedName
	items+=Item*;
Item:
	'item' name=ID;
QualifiedName:
	ID ('.'ID)*;

cannot parse this:

label flax.item.mybox
item Book
item MagicWand
item DiscoBall

It says "Missing RULE_ID at item".

I figured that any "keyword" cannot be used for matching the rule ID but I'm wondering why?

Also I noticed that the following piece of text seems valid:

label my     .     blue     .     box
item Book
item MagicWand
item DiscoBall

How can I disallow spaces in the QualifiedName rule?

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Re: Simple question about the lexer [message #1750317 is a reply to message #1750314]

Mon, 19 December 2016 20:13

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

you can use YourRule hidden(): ....

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Simple question about the lexer [message #1750318 is a reply to message #1750317]

Mon, 19 December 2016 20:19

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

p.s. and you have to allow a keyword like this:

MyID: ID | 'keyword1' | ... | 'keywordn';

and then use MyID instead of ID

or you escape the keyword like

^mykeyword

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Simple question about the lexer [message #1750466 is a reply to message #1750318]

Wed, 21 December 2016 10:46

Eric Salemi

Messages: 35
Registered: September 2016
Location: Belgium

Member

Hard-coding the keywords in the rule works (i.e no validation error) but IDEA still highlights it as it it were a keyword.

How can I disable this too?

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