1cc7e32e2d
The parser is no longer hard-coded to skip whitespace. Tokens such as newlines, whose characters overlap with the separator characters, can now be correctly recognized.
80 lines
No EOL
2.6 KiB
C++
80 lines
No EOL
2.6 KiB
C++
#include "compiler_spec_helper.h"
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#include "compiler/build_tables/rule_can_be_blank.h"
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#include "compiler/rules/metadata.h"
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#include "compiler/prepared_grammar.h"
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using namespace rules;
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using build_tables::rule_can_be_blank;
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START_TEST
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describe("checking if rules can be blank", [&]() {
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rule_ptr rule;
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it("returns false for basic rules", [&]() {
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AssertThat(rule_can_be_blank(sym("x")), IsFalse());
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AssertThat(rule_can_be_blank(str("x")), IsFalse());
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AssertThat(rule_can_be_blank(pattern("x")), IsFalse());
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});
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it("returns true for blanks", [&]() {
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AssertThat(rule_can_be_blank(blank()), IsTrue());
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});
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it("returns true for repeats", [&]() {
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AssertThat(rule_can_be_blank(repeat(str("x"))), IsTrue());
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});
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it("returns true for choices iff one or more sides can be blank", [&]() {
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rule = choice({ sym("x"), blank() });
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AssertThat(rule_can_be_blank(rule), IsTrue());
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rule = choice({ blank(), sym("x") });
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AssertThat(rule_can_be_blank(rule), IsTrue());
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rule = choice({ sym("x"), sym("y") });
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AssertThat(rule_can_be_blank(rule), IsFalse());
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});
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it("returns true for sequences iff both sides can be blank", [&]() {
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rule = seq({ blank(), str("x") });
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AssertThat(rule_can_be_blank(rule), IsFalse());
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rule = seq({ str("x"), blank() });
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AssertThat(rule_can_be_blank(rule), IsFalse());
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rule = seq({ blank(), choice({ sym("x"), blank() }) });
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AssertThat(rule_can_be_blank(rule), IsTrue());
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});
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it("ignores metadata rules", [&]() {
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rule = make_shared<rules::Metadata>(blank(), rules::MetadataValue(0));
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AssertThat(rule_can_be_blank(rule), IsTrue());
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rule = make_shared<rules::Metadata>(sym("one"), rules::MetadataValue(0));
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AssertThat(rule_can_be_blank(rule), IsFalse());
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});
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describe("checking recursively (by expanding non-terminals)", [&]() {
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PreparedGrammar grammar({
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{ "A", choice({
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seq({ sym("A"), sym("x") }),
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blank() }) },
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{ "B", choice({
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seq({ sym("B"), sym("y") }),
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sym("z") }) },
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}, {});
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it("terminates for left-recursive rules that can be blank", [&]() {
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rule = sym("A");
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AssertThat(rule_can_be_blank(rule, grammar), IsTrue());
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});
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it("terminates for left-recursive rules that can't be blank", [&]() {
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rule = sym("B");
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AssertThat(rule_can_be_blank(rule, grammar), IsFalse());
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});
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});
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});
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END_TEST |