87 lines
1.5 KiB
Erlang
87 lines
1.5 KiB
Erlang
Nonterminals
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grammar
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e_list
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e
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assignment
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add
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sub
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mult
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div
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idiv
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unary
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number
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unary
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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 -> e_list : '$1'.
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grammar -> '$empty' : [].
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e_list -> eol : [].
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e_list -> e : ['$1'].
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e_list -> e eol : ['$1'].
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e_list -> eol e_list : '$2'.
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e_list -> e eol e_list : ['$1'|'$3'].
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%% Minimum expressions
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e -> var : '$1'.
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e -> number : '$1'.
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e -> '(' e ')' : '$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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e -> mult : '$1'.
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e -> div : '$1'.
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e -> idiv : '$1'.
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e -> assignment : '$1'.
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e -> add : '$1'.
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e -> sub : '$1'.
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e -> unary : '$1'.
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assignment -> var '=' e :
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{ '=', ?meta('$2'), [?var('$1'), '$3'] }.
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%% Arithmetic operations
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add -> e '+' e :
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{ '+', ?meta('$2'), ['$1', '$3'] }.
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sub -> e '-' e :
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{ '-', ?meta('$2'), ['$1', '$3'] }.
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mult -> e '*' e :
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{ '*', ?meta('$2'), ['$1', '$3'] }.
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div -> e '/' e :
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{ '/', ?meta('$2'), ['$1', '$3'] }.
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idiv -> e '//' e :
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{ 'div', ?meta('$2'), ['$1', '$3'] }.
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unary -> '+' e : { '+', ?meta('$1'), ?op('$1'), '$2' }.
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unary -> '-' e : { '-', ?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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