42 lines
1.1 KiB
PHP
42 lines
1.1 KiB
PHP
/*
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* Corresponds to the following grammar, with E as start:
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*
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* E : T [ ('+'|'-') T ]*
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* T : F [ ('*'|'/') F ]*
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* F : [ ('-'|'+') ]* P
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* P : G ('^') F
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* G : ( '(' E ')' | CONSTANT ) [ '!' ]
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*
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* G, the operand, is parsed by a specific function to start the process.
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*/
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#ifndef OP
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# define OP(Kind, Prio, Assoc, Fix, /* Operator string */ ...)
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#endif
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#ifndef BINOP
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# define BINOP(Kind, Prio, Assoc, ...) \
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OP(Kind, Prio, Assoc, OP_INFIX, __VA_ARGS__)
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#endif
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#ifndef PREOP
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# define PREOP(Kind, Prio, Assoc, ...) \
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OP(Kind, Prio, Assoc, OP_PREFIX, __VA_ARGS__)
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#endif
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#ifndef POSTOP
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# define POSTOP(Kind, Prio, Assoc, ...) \
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OP(Kind, Prio, Assoc, OP_POSTFIX, __VA_ARGS__)
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#endif
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BINOP (BINOP_PLUS, 1, ASSOC_LEFT, '+', 0)
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BINOP (BINOP_MINUS, 1, ASSOC_LEFT, '-', 0)
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BINOP (BINOP_TIMES, 2, ASSOC_LEFT, '*', 0)
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BINOP (BINOP_DIVIDES, 2, ASSOC_LEFT, '/', 0)
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BINOP (BINOP_POW, 4, ASSOC_RIGHT, '^', 0)
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PREOP (UNOP_NEGATE, 3, ASSOC_RIGHT, '-', 0)
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PREOP (UNOP_IDENTITY, 3, ASSOC_RIGHT, '+', 0)
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POSTOP(UNOP_FACT, 5, ASSOC_NONE, '!', 0)
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#undef BINOP
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#undef PREOP
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#undef POSTOP
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#undef OP
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