Talk:Wirth syntax notation

Philosophy: Logic / Language / Analytic Low‑importance

This article is within the scope of WikiProject Philosophy, a collaborative effort to improve the coverage of content related to philosophy on Wikipedia. If you would like to support the project, please visit the project page, where you can get more details on how you can help, and where you can join the general discussion about philosophy content on Wikipedia.PhilosophyWikipedia:WikiProject PhilosophyTemplate:WikiProject PhilosophyPhilosophy articles

Low

This article has been rated as Low-importance on the project's importance scale.

Associated task forces:
/
	Logic
	Philosophy of language
	Analytic philosophy

Schorre metacompilers came first

Latest comment: 9 years ago1 comment1 person in discussion

Wirth syntax notation was not really such a new concept. Many meta compilers predate this notation. They are a bit different, but basically the identical concepts we see in META II(1964), TREEMETA(1968) and CWIC(1970). Not novel or new. Then again Parsing Expression Grammar is not a new or different concept. These grammars are expressing the syntax analysis using top down order dependent rules. The opposite of languages like BNF (Backus–Naur Form). Designing a parser from a generative language like BNF is a difficult endeavor. They did use the .EMPTY notation instead of [ ] for expressing optional constructs. $ for zero or more. The braces {} and brackets [] are used in code production constructs.

Basic CWIC, TREEMETA and METAII syntax rule syntax, excluding production syntax:

SYNTAX = ".SYNTAX" $RULE ".STOP" ID ID;
RULE   = ID "=" EXPR ";";
EXPR   = TEST $TEST ("/" ALTR / "\" BALT / .EMPTY);
ALTR   = TEST $TEST ("/" ALTR / .EMPTY);
BALT   = TEST $TEST ("\" BALT / .EMPTY);
TEST   = ID / LITERL / "(" EXPR ")" / ".EMPTY" / ".FAIL";
LITERL = (","/"-"/"+"/"?") STRING;
STRING .. """" $(-"""" .ANY / """""" ,"""") """";
ID.. LET $SYM_CHAR;
LET:  "A"/"B"/"C"/"D"/"E"/"F"/"G"/"H"/"I"/"J"/"K"/"L"/"M"
.    /"N"/"O"/"P"/"Q"/"R"/"S"/"T"/"U"/"V"/"W"/"X"/"Y"/"Z";
DGT:  "0"/"1"/"2"/"3"/"4"/"5"/"6"/"7"/"8"/"9";
SYM_CHR: LET/DGT/"_";

META I, META II and TREEMETA did not have the BALT. The BALT is a CWIC backtracking alternate. Non-backtracking and backtracking alternants can not be mixed within an expreszion. Note that an expression may be grouped allowing different alternatives within a rule. A modern-day version could use the | and || for alternative operators.

META II used braces around code productions. Square brackets were used in in TREEMETA to construct abstract syntax trees. In CWIC square brackets were used in generator function calls.

Note. The Lexical token rules ID and STRING use the ".." rule identifying operator. And the ":" operator for character class rules. "..." has been used for .EMPTY in recent Metacompilers. Metacompilers are easly changed and quickly evolved once METAII documents were publisher. CWIC is described in an ACM 1970 publications.

All predate Writh notation. These are for example only. May not be correct or have errors.

Steamerandy (talk) 23:28, 3 January 2015 (UTC) Steamerandy (talk) 19:11, 4 October 2014 (UTC)Reply

Add topic