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| ====== Buzz Syntax BNF Specification ====== | |
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| ===== Tokens ===== | |
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| An **identifier** in Buzz is defined by this regular expression: | |
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| [[:alpha:]_][[:alnum:]_]* | |
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| The recognized tokens are: | |
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| ^ Token ^ Id ^ | |
| | //identifier// | ''TOKID'' | | |
| | //numeric constant// | ''TOKCONST'' | | |
| | '''''_string_''''' ''"''_string_''"'' | ''TOKSTRING'' | | |
| | ''var'' | ''TOKVAR'' | | |
| | ''nil'' | ''TOKNIL'' | | |
| | ''if'' | ''TOKIF'' | | |
| | ''else'' | ''TOKELSE'' | | |
| | ''function'' | ''TOKFUN'' | | |
| | ''return'' | ''TOKRETURN'' | | |
| | ''for'' | ''TOKFOR'' | | |
| | ''while'' | ''TOKWHILE'' | | |
| | ''and'', ''or'' | ''TOKANDOR'' | | |
| | ''not'' | ''TOKNOT'' | | |
| | ''+'', ''-'' | ''TOKADDSUB'' | | |
| | ''*'', ''/'' | ''TOKMULDIV'' | | |
| | ''%'' | ''TOKMOD'' | | |
| | ''^'' | ''TOKPOW'' | | |
| | ''{'' | ''TOKBLOCKOPEN'' | | |
| | ''}'' | ''TOKBLOCKCLOSE'' | | |
| | ''('' | ''TOKPAROPEN'' | | |
| | '')'' | ''TOKPARCLOSE'' | | |
| | ''['' | ''TOKIDXOPEN'' | | |
| | '']'' | ''TOKIDXCLOSE'' | | |
| | '';'' ''\n'' | ''TOKSTATEND'' | | |
| | '','' | ''TOKLISTSEP'' | | |
| | ''='' | ''TOKASSIGN'' | | |
| | ''.'' | ''TOKDOT'' | | |
| | ''<'' ''<='' ''>'' ''>='' ''=='' ''!='' | ''TOKCMP'' | | |
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| ===== Grammar ===== | |
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| script ::= statlist | |
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| statlist ::= stat | statlist stat | |
| stat ::= <nil> | vardef | fundef | if | loop | command | |
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| block ::= TOKBLOCKOPEN statlist TOKBLOCKCLOSE | |
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| vardef ::= TOKVAR TOKID | TOKVAR TOKID assignment | |
| fundef ::= TOKFUN TOKID TOKPAROPEN idlist TOKPARCLOSE block | |
| if ::= TOKIF TOKPAROPEN condition TOKPARCLOSE block endif | |
| endif ::= <nil> | TOKELSE block | |
| loop ::= forloop | whileloop | |
| forloop ::= TOKFOR TOKPAROPEN idref TOKASSIGN expression TOKLISTSEP condition TOKLISTSEP idref TOKASSIGN expression TOKPARCLOSE block | |
| whileloop ::= TOKWHILE TOKPAROPEN condition TOKPARCLOSE block | |
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| conditionlist ::= condition | conditionlist TOKLISTSEP condition | |
| condition ::= comparison | condition TOKANDOR comparison | |
| comparison ::= TOKPAROPEN condition TOKPARCLOSE | NOT comparison | expression | expression TOKCMP expression | |
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| expression ::= product | expression TOKADDSUB product | |
| product ::= modulo | product TOKMULDIV modulo | |
| modulo ::= power | modulo TOKMOD power | |
| power ::= operand powerrest | |
| powerrest ::= <nil> | TOKPOW power | |
| operand ::= TOKNIL | TOKBLOCKOPEN assignmentlist TOKBLOCKCLOSE | TOKCONST | TOKSTRING | TOKPAROPEN expression TOKPARCLOSE | TOKADDSUB power | idref | lambda | |
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| command ::= idref | idref assignment | TOKRETURN expression | |
| assignment ::= TOKASSIGN expression | |
| assignmentlist ::= <nil> | TOKDOT idref TOKASSIGN expression | TOKDOT TOKCONST TOKASSIGN expression | assignmentlist TOKLISTSEP assignmentlist | |
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| idlist ::= <nil> | TOKID | idlist TOKLISTSEP TOKID | |
| idreflist ::= idref | idreflist TOKLISTSEP idref | |
| idref ::= TOKID | idref TOKDOT TOKID | idref TOKIDXOPEN expression TOKIDXCLOSE | idref TOKPAROPEN conditionlist TOKPARCLOSE | |
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| lambda ::= TOKFUN TOKPAROPEN idlist TOKPARCLOSE block | |