Grammar: Difference between revisions

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The following one-line '''grammar''' describes the essence of k syntax<ref>[https://kparc.com/k.txt kparc.com/k.txt]</ref>:

E:E;e|e e:nve|te| t:n|v v:tA|V n:t[E]|(E)|{E}|N

or in more verbose form:

<expr> ::= <noun> <verb> <expr> | <term> <expr> | empty

Further, <tt><Adverb></tt> <tt><Verb></tt> <tt><Noun></tt> can be defined, with minor variations between dialects, as:

<Adverb> ::= "'" | "/" | "\" | "':" | "/:" | "\:"

<Verb> ::= <Verb1> | <Verb1> ":"

<Verb1> ::= ":" | "+" | "-" | "*" | "%" | "!" | "&" | "|" | "<" | ">" | "=" | "~" | "," |

"^" | "#" | "_" | "$" | "?" | "@" | "." | <Digit> ":"

<Chars> ::= <Chars> <Char> | empty

<Char> ::= "\0" | "\t" | "\n" | "\r" | '\"' | "\\" | any

<Bytes> ::= <Bytes> <Hex> <Hex> | empty

<Digit> ::= "0" | .. | "9"

<Hex> ::= <Digit> | "a" | .. | "f"

<Letter> ::= "A" | .. | "Z" | "a" | .. | "z"

An important property of k syntax is it's ''static parsability'' - a parse tree can be built just by looking at the source code, without any knowledge of the values variables have at runtime.