附录 A Erlang 语法参考
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小牛编辑
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2023-12-01
这部分语法参考是 LALR 语法的改编版本。
此语法和严格的 LALR 语法对 match_expr 有不同理解。 match_expr 中等号左边可以是一个模式或者表达式， Erlang 编译器会在语义分析时确定其含义。
| 类型 | 优先级 | 运算符 |
|---|---|---|
| Nonassoc | 0 | 'catch'. |
| Right | 200 | '='. |
| Right | 200 | '!'. |
| Left | 300 | add op. |
| Left | 400 | mult op. |
| Nonassoc | 500 | prefix op. |
| 编号 | 非终结符 | 表达式 |
|---|---|---|
| 1 | add op | := "+" | "-" | "bor" | "bxor" | "bsl" | "bsr" |
| 2 | comp_op | := "==" | "/=" | "=<" | "<" | ">=" | ">" | "=:=" | "=/=" |
| 3 | mult_op | := "*" | "/" | "div" | "rem" | "band" |
| 4 | prefix_op | := "+" | "-" | "bnot" |
| 5 | basic_type | := "atom" | "number" | "string" | "var" | "true" |
| 6 | pattern | := basic_type | pattern_list | pattern_tuple |
| 7 | pattern_list | := "[" "]" | "[" pattern pattern tail "]" |
| 8 | pattern_tail | := "|" pattern | "," pattern pattern_tail | ε |
| 9 | pattern_tuple | := "{" "}" | "{" patterns "}" |
| 10 | patterns | := pattern | pattern "," patterns |
| 11 | expr | := basic_type | list | tuple | function_call | expr add op expr | expr mult_op expr | prefix_op expr | "(" expr ")" | "begin" exprs "end" | "catch" expr | case_expr | if_expr | receive_expr | match_expr | send expr |
| 12 | list | := "[" "]" | "[" expr expr_tail "]" |
| 13 | expr_tail | := "|" expr | "," expr expr_tail | ε |
| 14 | tuple | := "{" "}" | "{" exprs "}" |
| 15 | function_call | := "atom" "(" parameter_list ")" | "atom" ":" "atom" "(" parameter_list ")" |
| 16 | parameter_list | := exprs | ε |
| 17 | case_expr | := "case" expr "of" cr_clauses "end" |
| 18 | cr_clause | := pattern clause_guard clause_body |
| 19 | cr_clauses | := cr_clause | cr_clause ";" cr_clauses |
| 20 | if_expr | := "if" if_clauses "end" |
| 21 | if_clause | := guard clause_body |
| 22 | if_clauses | := if_clause | if_clause ";" if_clauses |
| 23 | receive_expr | := "receive" "after" expr clause_body "end" | "receive" cr_clauses "end" | "receive" cr_clauses "after" expr clause_body "end" |
| 24 | match_expr | := expr "=" expr |
| 25 | send expr | := expr "!" expr |
| 26 | exprs | := expr | expr "," exprs |
| 27 | guard_expr | := basic_type | guard_expr_list | guard_expr_tuple | guard_call | "(" guard_expr ")" | guard_expr add op guard_expr | guard_expr mult_op guard_expr | prefix_op guard_expr |
| 28 | guard_expr_list | := "[" "]" | "[" guard_expr guard_expr_tail "]" |
| 29 | guard_expr_tail | := "|" guard_expr | "," guard_expr guard_expr_tail | ε |
| 30 | guard_expr_tuple | := "{" "}" | "{" guard_exprs "}" |
| 31 | guard_exprs | := guard_expr | guard_expr "," guard_exprs |
| 32 | guard_call | := "atom" "(" guard_parameter_list ")" |
| 33 | guard_parameter_list | := guard_exprs | ε |
| 34 | bif_test | := "atom" "(" guard_parameter_list ")" |
| 35 | guard_test | := bif_test | guard_expr comp_op guard_expr |
| 36 | guard_tests | := guard_test | guard_test "," guard_tests |
| 37 | guard | := "true" | guard_tests |
| 38 | function_clause | := clause_head clause_guard clause_body |
| 39 | clause_head | := "atom" "(" formal parameter_list ")" |
| 40 | formal parameter_list | := patterns | ε |
| 41 | clause_guard | := "when" guard | ε |
| 42 | clause_body | := "->" exprs |
| 43 | function | := function_clause | function_clause ";" function |
| 44 | attribute | := pattern | "[" farity_list "]" | "atom" "," "[" farity_list "]" |
| 45 | farity_list | := farity | farity "," farity_list |
| 46 | farity | := "atom" "/" "number" |
| 47 | form | := "-" "atom" "(" attribute ")" | function |
| 非终结符 | 编号 |
|---|---|
| add_op | *1 11 27 |
| attribute | *44 47 |
| basic_type | *5 6 11 27 |
| bif_test | *34 35 |
| case_expr | 11 *17 |
| clause_body | 18 21 23 38 *42 |
| clause_guard | 18 38 *41 |
| clause_head | 38 *39 |
| comp_op | *2 35 |
| cr_clause | *18 19 |
| cr_clauses | 17 *19 19 23 |
| expr | *11 11 12 13 17 23 24 25 26 |
| expr_tail | 12 *13 13 |
| exprs | 11 14 16 *26 26 42 |
| farity | 45 *46 |
| farity_list | 44 *45 45 |
| form | *47 |
| formal_parameter_list | 39 *40 |
| function | *43 43 47 |
| function_call | 11 *15 |
| function_clause | *38 43 |
| guard | 21 *37 41 |
| guard_call | 27 *32 |
| guard_expr | *27 27 28 29 31 35 |
| guard_expr_list | 27 *28 |
| guard_expr_tail | 28 *29 29 |
| guard_expr_tuple | 27 *30 |
| guard_exprs | 30 *31 31 33 |
| guard_parameter_list | 32 *33 34 |
| guard_test | *35 36 |
| guard_tests | *36 36 37 |
| if_clause | *21 22 |
| if_clauses | 20 *22 22 |
| if_expr | 11 *20 |
| list | 11 *12 |
| match_expr | 11 *24 |
| mult_op | *3 11 27 |
| parameter_list | 15 *16 |
| pattern | *6 7 8 10 18 44 |
| pattern_list | 6 *7 |
| pattern_tail | 7 *8 8 |
| pattern_tuple | 6 *9 |
| patterns | 9 *10 10 40 |
| prefix_op | *4 11 27 |
| receive_expr | 11 *23 |
| send_expr | 11 *25 |
| tuple | 11 *14 |