forked from xxq250/Nasal-Interpreter
77 lines
3.0 KiB
C++
77 lines
3.0 KiB
C++
/*
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<>术语符号
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|并列选项，只能选一个
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*/
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//basic elements
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<identifier> ::= IDENTIFIER
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<number> ::= NUMBER
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<string> ::= STRING
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//scalar
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<use_identifier> ::= <identifier>|<array_search>|<hash_search>
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<scalar> ::= <number>|<string>|<array>|<hash>|<use_identifier>|<use_function>
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<scalars> ::= <scalar> <,> <scalar>
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<scalars> ::= <scalars> <,> <scalar>
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//array
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<array_search> ::= <use_identifier> <[> <number> <]>
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<array> ::= <[> <scalar>|<scalars> <]>
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//hash
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<hash_search> ::= <use_identifier> <[> <string> <]>
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<hash_member> ::= <identifier> <:> <scalar>
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<hash_members> ::= <hash_member> <,> <hash_member>
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<hash_members> ::= <hash_members> <,> <hash_member>
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<hash> ::= <{> <hash_member>|<hash_members> <}>
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//function
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<parameter> ::= <scalar>
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<parameters> ::= <scalars>
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<function> ::= <func> <(> <parameter>|<parameters> <)> <{> <statement>|<statements> <}>
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<use_function> ::= <use_identifier> <(> <parameter>|<parameters> <)>
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//definition & assignment
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<definition> ::= <var> <identifier> <=> <scalar>|<function> <;>
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<assignment> ::= <identifier> <=> <scalar> <;>
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//loop
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<loop_condition> ::= <statement>|<statements> <;> <condition>|<conditions> <;> <statement>|<statements>
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<loop> ::= <for> <(> <loop_condition> <)> <statement>|<{> <statement>|<statements> <}>
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<loop> ::= <while> <(> <condition>|<conditions> <)> <statement>|<{> <statement>|<statements> <}>
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//if else
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<condition_link_operator> ::= <and>|<or>|<!>
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<cmp_operator> ::= <==>|<>>|<<>|<<=>|<>=>|<!=>|<condition_link_operator>
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<condition> ::= <scalar>
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<condition> ::= <scalar> <cmp_operator> <scalar>
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<conditions> ::= <(> <condition> <)> <condition_link_operator> <(> <condition> <)>
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<conditions> ::= <(> <conditions> <)> <condition_link_operator> <(> <condition> <)>
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<conditions> ::= <(> <condition> <)> <condition_link_operator> <(> <conditions> <)>
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<conditions> ::= <conditions> <condition_link_operator> <(> <condition> <)>
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<conditions> ::= <conditions> <condition_link_operator> <(> <conditions> <)>
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//(e==1) && (e==2)
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//((e==1) && (e==2)) && (e==3)
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//(e==1) && ((e==2) && (e==3))
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//(e==1) && (e==2) && (e==3) && ((e==4) && (e==5))
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<_if> ::= <if> <(> <condition>|<conditions> <)> <statement>
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<_if> ::= <if> <(> <condition>|<conditions> <)> <{> <statement>|<statements> <}>
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<_else> ::= <else> <statement>
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<_else> ::= <else> <{> <statement>|<statements> <}>
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<else_if> ::= <else> <if> <(> <condition>|<conditions> <)> <statement>
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<else_if> ::= <else> <if> <(> <condition>|<conditions> <)> <{> <statement>|<statements> <}>
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<else_ifs> ::= <else_if> <else_if>
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<else_ifs> ::= <else_ifs> <else_if>
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<choose> ::= <_if>
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<choose> ::= <_if> <_else>
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<choose> ::= <_if> <else_if>
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<choose> ::= <_if> <else_ifs>
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<choose> ::= <_if> <else_if> <_else>
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<choose> ::= <_if> <else_ifs> <_else>
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//statement
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<func_return> ::= <return> <scalar>
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<statement> ::= <definition>|<assignment>|<loop>|<choose>|<use_function>|<func_return> <;>
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<statements> ::= <statement> <statement>
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<statements> ::= <statements> <statement>
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