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Add parse_theorem and parse_definition

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-08-18 12:48:02 -07:00
parent 5d2027d889
commit ae523e33b4
2 changed files with 56 additions and 14 deletions
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12
examples/ex3.lean Normal file
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@ -0,0 +1,12 @@
Definition xor (x y : Bool) : Bool := (not x) = y
Infixr 50 ⊕ xor
Show xor true false
Eval xor true true
Eval xor true false
Variable a : Bool
Show a ⊕ a ⊕ a
Check Subst
Theorem EM2 (a : Bool) : a \/ (not a) :=
Case (fun x : Bool, x \/ (not x)) Trivial Trivial a
Check EM2
Check EM2 a

58
src/frontend/parser.cpp
View file

@ -80,6 +80,7 @@ struct parser_fn {
bool curr_is_identifier() const { return curr() == scanner::token::Id; }
bool curr_is_lparen() const { return curr() == scanner::token::LeftParen; }
bool curr_is_colon() const { return curr() == scanner::token::Colon; }
void check_identifier(char const * msg) { if (!curr_is_identifier()) throw parser_error(msg); }
name check_identifier_next(char const * msg) { check_identifier(msg); name r = curr_name(); next(); return r; }
@ -87,6 +88,7 @@ struct parser_fn {
void check_comma_next(char const * msg) { check_next(scanner::token::Comma, msg); }
void check_lparen_next(char const * msg) { check_next(scanner::token::LeftParen, msg); }
void check_rparen_next(char const * msg) { check_next(scanner::token::RightParen, msg); }
void check_assign_next(char const * msg) { check_next(scanner::token::Assign, msg); }
void check_name(name const & op, char const * msg) { if(!curr_is_identifier() || curr_name() != op) throw parser_error(msg); }
void check_name_next(name const & op, char const * msg) { check_name(op, msg); next(); }
@ -315,13 +317,8 @@ struct parser_fn {
}
}
expr parse_abstraction(bool is_lambda) {
next();
local_decls::mk_scope scope(m_local_decls);
buffer<std::pair<name, expr>> bindings;
parse_bindings(bindings);
check_comma_next("invalid abstraction, ',' expected");
expr result = parse_expr();
expr mk_abstraction(bool is_lambda, buffer<std::pair<name, expr>> const & bindings, expr const & body) {
expr result = body;
unsigned i = bindings.size();
while (i > 0) {
--i;
@ -333,6 +330,16 @@ struct parser_fn {
return result;
}
expr parse_abstraction(bool is_lambda) {
next();
local_decls::mk_scope scope(m_local_decls);
buffer<std::pair<name, expr>> bindings;
parse_bindings(bindings);
check_comma_next("invalid abstraction, ',' expected");
expr result = parse_expr();
return mk_abstraction(is_lambda, bindings, result);
}
expr parse_lambda() {
return parse_abstraction(true);
}
@ -426,11 +433,38 @@ struct parser_fn {
return e;
}
void parse_definition() {
void parse_def_core(bool is_definition) {
next();
expr type, val;
name id = check_identifier_next("invalid definition, identifier expected");
check_colon_next("invalid definition, ':' expected");
// TODO
if (curr_is_colon()) {
next();
type = elaborate(parse_expr());
check_assign_next("invalid definition, ':=' expected");
val = elaborate(parse_expr());
} else {
local_decls::mk_scope scope(m_local_decls);
buffer<std::pair<name, expr>> bindings;
parse_bindings(bindings);
check_colon_next("invalid definition, ':' expected");
expr type_body = parse_expr();
check_assign_next("invalid definition, ':=' expected");
expr val_body = parse_expr();
type = elaborate(mk_abstraction(false, bindings, type_body));
val = elaborate(mk_abstraction(true, bindings, val_body));
}
if (is_definition)
m_frontend.add_definition(id, type, val);
else
m_frontend.add_theorem(id, type, val);
}
void parse_definition() {
parse_def_core(true);
}
void parse_theorem() {
parse_def_core(false);
}
void parse_variable() {
@ -441,10 +475,6 @@ struct parser_fn {
m_frontend.add_var(id, type);
}
void parse_theorem() {
// TODO
}
void parse_axiom() {
next();
name id = check_identifier_next("invalid axiom, identifier expected");