105 lines
1.9 KiB
Erlang
105 lines
1.9 KiB
Erlang
Nonterminals
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grammar
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expr_list
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expr
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assign_expr
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add_expr
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sub_expr
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mult_expr
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div_expr
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idiv_expr
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unary_expr
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max_expr
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number
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unary_op
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add_op
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sub_op
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mult_op
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div_op
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idiv_op
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.
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Terminals
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var float integer eol
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'+' '-' '*' '/' '//' '(' ')' '='
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.
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Rootsymbol grammar.
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Endsymbol '$end'.
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Right 100 '='.
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Left 300 '+'.
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Left 300 '-'.
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Left 400 '*'.
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Left 400 '/'.
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Left 400 '//'.
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grammar -> expr_list : '$1'.
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grammar -> '$empty' : [].
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expr_list -> eol : [].
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expr_list -> expr : ['$1'].
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expr_list -> expr eol : ['$1'].
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expr_list -> eol expr_list : '$2'.
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expr_list -> expr eol expr_list : ['$1'|'$3'].
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%% Minimum expressions
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max_expr -> var : '$1'.
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max_expr -> number : '$1'.
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max_expr -> '(' expr ')' : '$2'.
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%% Numbers
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number -> float : '$1'.
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number -> integer : ?e(3, '$1').
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%% Unary operator
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unary_op -> '+' : '$1'.
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unary_op -> '-' : '$1'.
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%% Infix Operators
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add_op -> '+' : '$1'.
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sub_op -> '-' : '$1'.
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mult_op -> '*' : '$1'.
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div_op -> '/' : '$1'.
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idiv_op -> '//' : '$1'.
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expr -> mult_expr : '$1'.
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expr -> div_expr : '$1'.
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expr -> idiv_expr : '$1'.
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expr -> assign_expr : '$1'.
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expr -> add_expr : '$1'.
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expr -> sub_expr : '$1'.
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expr -> unary_expr : '$1'.
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expr -> max_expr : '$1'.
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assign_expr -> var '=' expr :
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{ '=', ?meta('$2'), [?var('$1'), '$3'] }.
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%% Arithmetic operations
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add_expr -> expr add_op expr :
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{ '+', ?meta('$2'), ['$1', '$3'] }.
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sub_expr -> expr sub_op expr :
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{ '-', ?meta('$2'), ['$1', '$3'] }.
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mult_expr -> expr mult_op expr :
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{ '*', ?meta('$2'), ['$1', '$3'] }.
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div_expr -> expr div_op expr :
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{ '/', ?meta('$2'), ['$1', '$3'] }.
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idiv_expr -> expr idiv_op expr :
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{ 'div', ?meta('$2'), ['$1', '$3'] }.
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unary_expr -> unary_op expr :
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{ unary_op, ?meta('$1'), ?op('$1'), '$2' }.
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Erlang code.
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-define(e(N, Node), element(N, Node)).
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-define(op(Node), ?e(1, Node)).
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-define(char(Node), ?e(3, Node)).
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-define(meta(Node), [?line(Node)]).
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-define(line(Node), {line, ?e(2, Node)}).
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-define(var(Node), {?e(3, Node), [], 'Lytlang'}).
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