json: Support parsing true, false, and null

robinlinden · Jan 13, 2025 · a593af4 · a593af4
1 parent 0ea71b7
commit a593af4
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Showing 2 changed files with 68 additions and 0 deletions.
diff --git a/json/json.h b/json/json.h
@@ -106,11 +106,54 @@ class Parser {
         switch (*c) {
             case '"':
                 return parse_string();
+            case 't':
+                return parse_true();
+            case 'f':
+                return parse_false();
+            case 'n':
+                return parse_null();
             default:
                 return std::nullopt;
         }
     }
 
+    constexpr std::optional<Value> parse_true() {
+        std::ignore = consume(); // 't'
+        auto r = consume();
+        auto u = consume();
+        auto e = consume();
+        if (r != 'r' || u != 'u' || e != 'e') {
+            return std::nullopt;
+        }
+
+        return Value{true};
+    }
+
+    constexpr std::optional<Value> parse_false() {
+        std::ignore = consume(); // 'f'
+        auto a = consume();
+        auto l = consume();
+        auto s = consume();
+        auto e = consume();
+        if (a != 'a' || l != 'l' || s != 's' || e != 'e') {
+            return std::nullopt;
+        }
+
+        return Value{false};
+    }
+
+    constexpr std::optional<Value> parse_null() {
+        std::ignore = consume(); // 'n'
+        auto u = consume();
+        auto l1 = consume();
+        auto l2 = consume();
+        if (u != 'u' || l1 != 'l' || l2 != 'l') {
+            return std::nullopt;
+        }
+
+        return Value{Null{}};
+    }
+
     constexpr std::optional<Value> parse_string() {
         std::string value;
         std::ignore = consume(); // '"'

diff --git a/json/json_test.cpp b/json/json_test.cpp
@@ -44,5 +44,30 @@ int main() {
         a.expect_eq(json::parse(R"("hello\p")"), std::nullopt);
     });
 
+    s.add_test("true", [](etest::IActions &a) {
+        a.expect_eq(json::parse("true"), json::Value{true});
+        a.expect_eq(json::parse("tru0"), std::nullopt);
+        a.expect_eq(json::parse("tr00"), std::nullopt);
+        a.expect_eq(json::parse("t000"), std::nullopt);
+        a.expect_eq(json::parse("true!"), std::nullopt);
+    });
+
+    s.add_test("false", [](etest::IActions &a) {
+        a.expect_eq(json::parse("false"), json::Value{false});
+        a.expect_eq(json::parse("fals0"), std::nullopt);
+        a.expect_eq(json::parse("fal00"), std::nullopt);
+        a.expect_eq(json::parse("fa000"), std::nullopt);
+        a.expect_eq(json::parse("f0000"), std::nullopt);
+        a.expect_eq(json::parse("false!"), std::nullopt);
+    });
+
+    s.add_test("null", [](etest::IActions &a) {
+        a.expect_eq(json::parse("null"), json::Value{json::Null{}});
+        a.expect_eq(json::parse("nul0"), std::nullopt);
+        a.expect_eq(json::parse("nu00"), std::nullopt);
+        a.expect_eq(json::parse("n000"), std::nullopt);
+        a.expect_eq(json::parse("null!"), std::nullopt);
+    });
+
     return s.run();
 }