json: Support parsing arrays

robinlinden · Jan 14, 2025 · 38639e2 · 38639e2
1 parent f848bf0
commit 38639e2
Show file tree

Hide file tree

Showing 2 changed files with 56 additions and 0 deletions.
diff --git a/json/json.h b/json/json.h
@@ -18,6 +18,7 @@
 #include <string_view>
 #include <system_error>
 #include <tuple>
+#include <utility>
 #include <variant>
 #include <vector>
 
@@ -105,6 +106,7 @@ class Parser {
         return v;
     }
 
+    // NOLINTNEXTLINE(misc-no-recursion)
     constexpr std::optional<Value> parse_value() {
         skip_whitespace();
         auto c = peek();
@@ -121,11 +123,50 @@ class Parser {
                 return parse_false();
             case 'n':
                 return parse_null();
+            case '[':
+                return parse_array();
             default:
                 return std::nullopt;
         }
     }
 
+    // NOLINTNEXTLINE(misc-no-recursion)
+    constexpr std::optional<Value> parse_array() {
+        std::ignore = consume(); // '['
+        if (peek() == ']') {
+            std::ignore = consume();
+            return Array{};
+        }
+
+        Array array;
+        while (true) {
+            auto v = parse_value();
+            if (!v) {
+                return std::nullopt;
+            }
+
+            array.values.push_back(*std::move(v));
+            skip_whitespace();
+
+            auto c = peek();
+            if (!c) {
+                return std::nullopt;
+            }
+
+            if (*c == ',') {
+                std::ignore = consume();
+                continue;
+            }
+
+            if (*c == ']') {
+                std::ignore = consume();
+                return array;
+            }
+
+            return std::nullopt;
+        }
+    }
+
     constexpr std::optional<Value> parse_true() {
         std::ignore = consume(); // 't'
         auto r = consume();

diff --git a/json/json_test.cpp b/json/json_test.cpp
@@ -9,6 +9,7 @@
 #include <optional>
 
 int main() {
+    using json::Value;
     etest::Suite s{};
 
     s.add_test("bad input", [](etest::IActions &a) {
@@ -70,5 +71,19 @@ int main() {
         a.expect_eq(json::parse("null!"), std::nullopt);
     });
 
+    s.add_test("array", [](etest::IActions &a) {
+        a.expect_eq(json::parse("[]"), Value{json::Array{}});
+        a.expect_eq(json::parse(R"(["1"])"), Value{json::Array{{Value{"1"}}}});
+        a.expect_eq(json::parse(R"([null, true, "hello", false, []])"),
+                Value{json::Array{
+                        {Value{json::Null{}}, Value{true}, Value{"hello"}, Value{false}, Value{json::Array{}}},
+                }});
+
+        a.expect_eq(json::parse("["), std::nullopt);
+        a.expect_eq(json::parse("[blah"), std::nullopt);
+        a.expect_eq(json::parse("[null"), std::nullopt);
+        a.expect_eq(json::parse("[null,"), std::nullopt);
+    });
+
     return s.run();
 }