Anniepoo / swipldcgtut

A tutorial for DCG's in swi-Prolog
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Incorporate Ulrichs comments #3

Open Anniepoo opened 11 years ago

Anniepoo commented 11 years ago

Niftoid - I'll add a note about this version of 'what the heck this is called' to the DCG tut when I get there.

----- Original Message ----- From: Ulrich Neumerkel ulrich@complang.tuwien.ac.at To: annie66us@yahoo.com Cc: Sent: Monday, August 26, 2013 10:51 AM Subject: Re: DCG

Dear Anne!

Back from the WG17 meeting, the name for the terminal symbols on the left-hand side of a grammar rule were again discussed.

right-hand context seems to lead to a lot of misunderstandings for linguists: A grammar rule is commonly presented as having a right-hand side RHS and a left-hand side LHS:

LHS --> RHS.

Now, the right-hand context appears in the left-hand side of the grammar rule.

This leads to a bit too much left-right issues.

Therefore, semicontext was agreed upon. It shares with the previous notion the same non-operational connotation, it is much shorter, and yet a blank slate.

It is semi, because a real context (in formal languages) occurs on both sides:

a, "c" --> b, "c".

Here, the letter c is the context. But if it does not appear in the body, it is not a context. Thus, a semicontext.

So, maybe you want to use it.

Best regards, Ulrich