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Fix bug in parse_arrow

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-08-19 16:14:19 -07:00
parent 53e4100e1f
commit f0b5ec8dfa
2 changed files with 9 additions and 0 deletions
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7
src/frontend/parser.cpp
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@ -59,6 +59,11 @@ static name g_overload_name(name(name(name(0u), "parser"), "overload"));
static expr g_overload = mk_constant(g_overload_name);
// ==========================================
// A name that can't be created by the user.
// It is used as placeholder for parsing A -> B expressions which
// are syntax sugar for (Pi (_ : A), B)
static name g_unused(name(0u), "parser");
/**
\brief Functional object for parsing
@ -471,6 +476,8 @@ class parser_fn {
/** \brief Parse <tt>expr '->' expr</tt>. */
expr parse_arrow(expr const & left) {
next();
mk_scope scope(*this);
register_binding(g_unused);
// The -1 is a trick to get right associativity in Pratt's parsers
expr right = parse_expr(g_arrow_precedence-1);
return mk_arrow(left, right);

2
src/tests/frontend/parser.cpp
View file

@ -34,6 +34,8 @@ static void tst1() {
parse(fe, "Show true && false Eval true && false");
parse(fe, "Infixl 35 & and Show true & false & false Eval true & false");
parse(fe, "Mixfixc 100 if then fi implies Show if true then false fi");
parse(fe, "Show Pi (A : Type), A -> A");
parse(fe, "Check Pi (A : Type), A -> A");
}
static void check(frontend const & fe, char const * str, expr const & expected) {