File name extension
The suggested extension for a POSE file is .pose. This appears to be unused by any common program.
MIME type
The tentative plan is to register the internet media type text/pose with IANA. In the meantime, text/x-pose is suggested.
Grammar
| expressions | = | (atmosphere* expression)* atmosphere* |
| atmosphere | = | whitespace | comment |
| whitespace | = | HT | VT | FF | space | newline |
| newline | = | CR | LF |
| comment | = | ';' and all subsequent characters until newline or eof |
| expression | = | list | string | number | symbol |
| list | = | '(' expressions ')' |
| string | = | '"' string-char* '"' |
| string-char | = | string-esc | any-char-except-backslash |
| string-esc | = | \\ | \" |
| number | = | '0' | decimal |
| decimal | = | minus? onenine digit* fraction? exponent? |
| fraction | = | '.' digit+ |
| exponent | = | 'e' sign digit+ |
| symbol | = | wordsym | signsym |
| wordsym | = | wordsym-1st wordsym-cont* |
| wordsym-1st | = | letter | punct-1st |
| wordsym-cont | = | letter | punct-cont | digit |
| signsym | = | sign signsym-rest? |
| signsym-rest | = | signsym-2nd signsym-cont* |
| signsym-2nd | = | letter | punct-cont |
| signsym-cont | = | letter | punct-cont | digit |
| punct-1st | = | '!' | '$' | '&' | '*' | '+' | '-' | '/' | '<' | '=' | '>' | '_' |
| punct-cont | = | punct-1st | '.' | '?' | '@' |
| letter | = | a-z | A-Z |
| digit | = | 0-9 |
| onenine | = | 1-9 |
| minus | = | '-' |
| sign | = | '-' | '+' |