Numeric Expression in Backus–Naur Form (BNF)

Definitions

1.syntax: the spelling and grammatical structure of a computer language

2. semantics: the meanings of the words and phrases

3. Lexical analysis, or tokenization is the process of converting a sequence of characters into a sequence of tokens (strings).

4. BNF: Backus–Naur form

history

In the 1950s, Noam Chomsky realized that rules for building syntactically correct sentences can be written as an equational definition. Chomsky called the definition a grammar. John Backus and Peter Naur independently discovered the same concept, and for this reason, a grammar is sometimes called BNF (Backus-Naur form) notation.

A grammar is a set of equations (rules), where each equation defines a set of phrases (strings of words).

Numeric Expression in BNF

EXPRESSION ::= TERM | EXPRESSION '+' TERM | EXPRESSION '-' TERM TERM ::= FACTOR | POWER | TERM '*' FACTOR | TERM '/' FACTOR | TERM '%' INTEGER POWER ::= FACTOR '**' FACTOR FACTOR ::= NUMBER | '(' EXPRESSION ')' NUMBER ::= INTEGER | FLOAT | REAL INTEGER ::= ['-' | '+'] DIGIT {DIGIT} FLOAT ::= INTEGER '.' {DIGIT} REAL ::= (INTEGER | FLOAT) ('e' | 'E') INTEGER DIGIT ::= '0' | '1' | ... | '8' | '9' [] enclose optional items () enclose optional items, one of which is required {} zero or more optional item; not required. | separate alternatives

Links

Syntax Of the Gentee Language In BNF Form

The syntax of C in Backus-Naur Form