Search results
Results from the WOW.Com Content Network
This leads to the idea of rewriting "modulo commutativity" where a term is in normal form if no rules but commutativity apply. [8] Weakly but not strongly normalizing rewrite system [9] The system {b → a, b → c, c → b, c → d} (pictured) is an example of a weakly normalizing but not strongly normalizing system.
This page was last edited on 19 March 2015, at 09:49 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may ...
The grammar = (,,,) is effectively the semi-Thue system (,), rewriting strings in exactly the same way; the only difference is in that we distinguish specific nonterminal symbols, which must be rewritten in rewrite rules, and are only interested in rewritings from the designated start symbol to strings without nonterminal symbols.
A string rewriting system or semi-Thue system is a tuple (,) where . is an alphabet, usually assumed finite. [5] The elements of the set (* is the Kleene star here) are finite (possibly empty) strings on , sometimes called words in formal languages; we will simply call them strings here.
"Don't repeat yourself" (DRY), also known as "duplication is evil", is a principle of software development aimed at reducing repetition of information which is likely to change, replacing it with abstractions that are less likely to change, or using data normalization which avoids redundancy in the first place.
The first rule reads: A S consists of a NP (noun phrase) followed by a VP (verb phrase). The second rule reads: A noun phrase consists of an optional Det followed by a N (noun). The third rule means that a N (noun) can be preceded by an optional AP (adjective phrase) and followed by an optional PP (prepositional phrase). The round brackets ...
The converse of a rewrite order is again a rewrite order. While rewrite orders exist that are total on the set of ground terms ("ground-total" for short), no rewrite order can be total on the set of all terms. [note 3] [5] A term rewriting system {l 1::=r 1,...,l n::=r n, ...} is terminating if its rules are a subset of a reduction ordering ...
Rewrite rules have names, e.g. simplify_conditional_assignment. Each rule has a "match this" and "replace by that" pattern pair separated by -> , in our example, on separate lines for readability. The patterns must correspond to language syntax categories; in this case, both patterns must be of syntax category statement also separated in ...