json-schema-to-grammar: fix order of props in C++, support non-string const/enum

common/json-schema-to-grammar.cpp

@@ -9,7 +9,7 @@
 #include <unordered_set>
 #include <vector>
 
-using json = nlohmann::json;
+using json = nlohmann::ordered_json;
 
 const std::string SPACE_RULE = "\" \"?";
 
@@ -124,7 +124,7 @@ static std::string replacePattern(const std::string & input, const std::regex &
 }
 
 static std::string format_literal(const std::string & literal) {
-    std::string escaped = replacePattern(json(literal).dump(), GRAMMAR_LITERAL_ESCAPE_RE, [&](const std::smatch & match) {
+    std::string escaped = replacePattern(literal, GRAMMAR_LITERAL_ESCAPE_RE, [&](const std::smatch & match) {
         char c = match.str()[0];
         return GRAMMAR_LITERAL_ESCAPES.at(c);
     });
@@ -137,7 +137,7 @@ class SchemaConverter {
     std::function<json(const std::string &)> _fetch_json;
     bool _dotall;
     std::map<std::string, std::string> _rules;
-    std::unordered_map<std::string, nlohmann::json> _refs;
+    std::unordered_map<std::string, json> _refs;
     std::unordered_set<std::string> _refs_being_resolved;
     std::vector<std::string> _errors;
     std::vector<std::string> _warnings;
@@ -413,7 +413,7 @@ class SchemaConverter {
             std::string prop_rule_name = visit(prop_schema, name + (name.empty() ? "" : "-") + prop_name);
             prop_kv_rule_names[prop_name] = _add_rule(
                 name + (name.empty() ? "" : "-") + prop_name + "-kv",
-                format_literal(prop_name) + " space \":\" space " + prop_rule_name
+                format_literal(json(prop_name).dump()) + " space \":\" space " + prop_rule_name
             );
             if (required.find(prop_name) != required.end()) {
                 required_props.push_back(prop_name);
@@ -495,7 +495,7 @@ class SchemaConverter {
         _rules["space"] = SPACE_RULE;
     }
 
-    void resolve_refs(nlohmann::json & schema, const std::string & url) {
+    void resolve_refs(json & schema, const std::string & url) {
         /*
         * Resolves all $ref fields in the given schema, fetching any remote schemas,
         * replacing each $ref with absolute reference URL and populates _refs with the
@@ -557,11 +557,7 @@ class SchemaConverter {
     }
 
     std::string _generate_constant_rule(const json & value) {
-        if (!value.is_string()) {
-            _errors.push_back("Only std::string constants are supported, got " + value.dump());
-            return "";
-        }
-        return format_literal(value.get<std::string>());
+        return format_literal(value.dump());
     }
 
     std::string visit(const json & schema, const std::string & name) {

common/json-schema-to-grammar.h

@@ -1,4 +1,4 @@
 #pragma once
 #include "json.hpp"
 
-std::string json_schema_to_grammar(const nlohmann::json& schema);
+std::string json_schema_to_grammar(const nlohmann::ordered_json& schema);

examples/json-schema-to-grammar.py

@@ -61,7 +61,7 @@ def __init__(self, *, prop_order, allow_fetch, dotall, raw_pattern):
 
     def _format_literal(self, literal):
         escaped = GRAMMAR_LITERAL_ESCAPE_RE.sub(
-            lambda m: GRAMMAR_LITERAL_ESCAPES.get(m.group(0)), json.dumps(literal)
+            lambda m: GRAMMAR_LITERAL_ESCAPES.get(m.group(0)), literal
         )
         return f'"{escaped}"'
 
@@ -308,8 +308,7 @@ def _resolve_ref(self, ref):
         return ref_name
 
     def _generate_constant_rule(self, value):
-        assert isinstance(value, str), f'Only string constants are supported, got {value}'
-        return self._format_literal(value)
+        return self._format_literal(json.dumps(value))
 
     def visit(self, schema, name):
         schema_type = schema.get('type')
@@ -428,7 +427,7 @@ def _build_object_rule(self, properties: List[Tuple[str, Any]], required: Set[st
             prop_rule_name = self.visit(prop_schema, f'{name}{"-" if name else ""}{prop_name}')
             prop_kv_rule_names[prop_name] = self._add_rule(
                 f'{name}{"-" if name else ""}{prop_name}-kv',
-                fr'{self._format_literal(prop_name)} space ":" space {prop_rule_name}'
+                fr'{self._format_literal(json.dumps(prop_name))} space ":" space {prop_rule_name}'
             )
         required_props = [k for k in sorted_props if k in required]
         optional_props = [k for k in sorted_props if k not in required]

examples/server/public/json-schema-to-grammar.mjs

@@ -48,7 +48,7 @@ export class SchemaConverter {
   }
 
   _formatLiteral(literal) {
-    const escaped = JSON.stringify(literal).replace(
+    const escaped = literal.replace(
       GRAMMAR_LITERAL_ESCAPE_RE,
       m => GRAMMAR_LITERAL_ESCAPES[m]
     );
@@ -327,10 +327,7 @@ export class SchemaConverter {
   }
 
   _generateConstantRule(value) {
-    if (typeof value !== 'string') {
-      throw new Error('Only string constants are supported, got ' + JSON.stringify(value));
-    }
-    return this._formatLiteral(value);
+    return this._formatLiteral(JSON.stringify(value));
   }
 
   visit(schema, name) {
@@ -346,9 +343,6 @@ export class SchemaConverter {
     } else if (Array.isArray(schemaType)) {
       return this._addRule(ruleName, this._generateUnionRule(name, schemaType.map(t => ({ type: t }))));
     } else if ('const' in schema) {
-      if (typeof schema.const !== 'string') {
-        throw new Error('Only string constants are supported, got ' + JSON.stringify(schema.const));
-      }
       return this._addRule(ruleName, this._generateConstantRule(schema.const));
     } else if ('enum' in schema) {
       const rule = schema.enum.map(v => this._generateConstantRule(v)).join(' | ');
@@ -457,7 +451,7 @@ export class SchemaConverter {
       const propRuleName = this.visit(propSchema, `${name ?? ''}${name ? '-' : ''}${propName}`);
       propKvRuleNames[propName] = this._addRule(
         `${name ?? ''}${name ? '-' : ''}${propName}-kv`,
-        `${this._formatLiteral(propName)} space ":" space ${propRuleName}`
+        `${this._formatLiteral(JSON.stringify(propName))} space ":" space ${propRuleName}`
       );
     }
     const requiredProps = sortedProps.filter(k => required.has(k));

examples/server/server.cpp

@@ -30,7 +30,7 @@
 #include <signal.h>
 #include <memory>
 
-using json = nlohmann::json;
+using json = nlohmann::ordered_json;
 
 bool server_verbose = false;
 bool server_log_json = true;

examples/server/utils.hpp

@@ -12,7 +12,7 @@
 
 #define DEFAULT_OAICOMPAT_MODEL "gpt-3.5-turbo-0613"
 
-using json = nlohmann::json;
+using json = nlohmann::ordered_json;
 
 // https://community.openai.com/t/openai-chat-list-of-error-codes-and-types/357791/11
 enum error_type {

tests/test-json-schema-to-grammar.cpp

@@ -90,7 +90,7 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
 
     test({
         FAILURE,
-        "invalid type type",
+        "invalid type",
         R"""({
             "type": 123
         })""",
@@ -193,21 +193,27 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
     });
 
     test({
-        FAILURE,
+        SUCCESS,
         "non-string const",
         R"""({
             "const": 123
         })""",
-        ""
+        R"""(
+            root ::= "123"
+            space ::= " "?
+        )"""
     });
 
     test({
-        FAILURE,
+        SUCCESS,
         "non-string enum",
         R"""({
-            "enum": [123]
+            "enum": ["red", "amber", "green", null, 42, ["foo"]]
         })""",
-        ""
+        R"""(
+            root ::= "\"red\"" | "\"amber\"" | "\"green\"" | "null" | "42" | "[\"foo\"]"
+            space ::= " "?
+        )"""
     });
 
     test({
@@ -378,28 +384,27 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
 
     test({
         SUCCESS,
-        "required props",
+        "required props in original order",
         R"""({
             "type": "object",
             "properties": {
-                "a": {
-                "type": "string"
-                },
-                "b": {
-                "type": "string"
-                }
+                "b": {"type": "string"},
+                "c": {"type": "string"},
+                "a": {"type": "string"}
             },
             "required": [
                 "a",
-                "b"
+                "b",
+                "c"
             ],
             "additionalProperties": false,
             "definitions": {}
         })""",
         R"""(
             a-kv ::= "\"a\"" space ":" space string
             b-kv ::= "\"b\"" space ":" space string
-            root ::= "{" space a-kv "," space b-kv "}" space
+            c-kv ::= "\"c\"" space ":" space string
+            root ::= "{" space b-kv "," space c-kv "," space a-kv "}" space
             space ::= " "?
             string ::=  "\"" (
                     [^"\\] |
@@ -458,13 +463,13 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
 
     test({
         SUCCESS,
-        "required + optional props",
+        "required + optional props each in original order",
         R"""({
             "properties": {
-                "a": {"type": "string"},
                 "b": {"type": "string"},
-                "c": {"type": "string"},
-                "d": {"type": "string"}
+                "a": {"type": "string"},
+                "d": {"type": "string"},
+                "c": {"type": "string"}
             },
             "required": ["a", "b"],
             "additionalProperties": false
@@ -473,14 +478,14 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
             a-kv ::= "\"a\"" space ":" space string
             b-kv ::= "\"b\"" space ":" space string
             c-kv ::= "\"c\"" space ":" space string
-            c-rest ::= ( "," space d-kv )?
             d-kv ::= "\"d\"" space ":" space string
-            root ::= "{" space a-kv "," space b-kv ( "," space ( c-kv c-rest | d-kv ) )? "}" space
+            d-rest ::= ( "," space c-kv )?
+            root ::= "{" space b-kv "," space a-kv ( "," space ( d-kv d-rest | c-kv ) )? "}" space
             space ::= " "?
             string ::=  "\"" (
                     [^"\\] |
                     "\\" (["\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F])
-                    )* "\"" space
+                )* "\"" space
         )"""
     });
 
@@ -648,16 +653,16 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
             "$ref": "#/definitions/MyType",
             "definitions": {
                 "MyType": {
-                "type": "object",
-                "properties": {
-                    "a": {
-                    "type": "string"
-                    }
-                },
-                "required": [
-                    "a"
-                ],
-                "additionalProperties": false
+                    "type": "object",
+                    "properties": {
+                        "a": {
+                            "type": "string"
+                        }
+                    },
+                    "required": [
+                        "a"
+                    ],
+                    "additionalProperties": false
                 }
             }
         })""",
@@ -683,10 +688,10 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
             ],
             "definitions": {
                 "foo": {
-                "properties": {"a": {"type": "number"}}
+                    "properties": {"a": {"type": "number"}}
                 },
                 "bar": {
-                "properties": {"b": {"type": "number"}}
+                    "properties": {"b": {"type": "number"}}
                 }
             },
             "type": "object"
@@ -720,16 +725,16 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
             ],
             "definitions": {
                 "foo": {
-                "properties": {"a": {"type": "number"}}
+                    "properties": {"a": {"type": "number"}}
                 },
                 "bar": {
-                "properties": {"b": {"type": "number"}}
+                    "properties": {"b": {"type": "number"}}
                 },
                 "bam": {
-                "properties": {"c": {"type": "number"}}
+                    "properties": {"c": {"type": "number"}}
                 },
                 "baz": {
-                "properties": {"d": {"type": "number"}}
+                    "properties": {"d": {"type": "number"}}
                 }
             },
             "type": "object"
@@ -757,15 +762,15 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
                 "properties": {
                     "number": {
                     "type": "object",
-                    "properties": {
-                        "root": {
-                        "type": "number"
-                        }
-                    },
-                    "required": [
-                        "root"
-                    ],
-                    "additionalProperties": false
+                        "properties": {
+                            "root": {
+                                "type": "number"
+                            }
+                        },
+                        "required": [
+                            "root"
+                        ],
+                        "additionalProperties": false
                     }
                 },
                 "required": [
@@ -796,7 +801,7 @@ static void test_all(const std::string & lang, std::function<void(const TestCase
 int main() {
     test_all("C++", [](const TestCase & tc) {
         try {
-            tc.verify(json_schema_to_grammar(nlohmann::json::parse(tc.schema)));
+            tc.verify(json_schema_to_grammar(nlohmann::ordered_json::parse(tc.schema)));
             tc.verify_status(SUCCESS);
         } catch (const std::runtime_error & ex) {
             fprintf(stderr, "Error: %s\n", ex.what());