From 82fca76bdd4183593702d80c5c41520e8b9d9ad0 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Wed, 7 Feb 2024 13:45:29 +0200
Subject: Tweak $json.*() function names and semantics

---
 libbuild2/functions-json.cxx   | 48 ++++++++++++++++++++++++++++++++----------
 tests/function/json/testscript | 38 ++++++++++++++++-----------------
 2 files changed, 56 insertions(+), 30 deletions(-)

diff --git a/libbuild2/functions-json.cxx b/libbuild2/functions-json.cxx
index d7265ba..ae5bd77 100644
--- a/libbuild2/functions-json.cxx
+++ b/libbuild2/functions-json.cxx
@@ -14,7 +14,7 @@ using namespace std;
 namespace build2
 {
   static size_t
-  find_index (const json_value& a, value v)
+  array_find_index (const json_value& a, value v)
   {
     if (a.type != json_type::array)
       fail << "expected json array instead of " << to_string (a.type)
@@ -97,7 +97,7 @@ namespace build2
       fail << "json object member expected instead of " << v.type << endf;
     };
 
-    // $size(<json>)
+    // $value_size(<json>)
     //
     // Return the size of a JSON value.
     //
@@ -109,7 +109,7 @@ namespace build2
     // string. To get the length call `$string.size()` instead by casting the
     // JSON value to the `string` value type.
     //
-    f["size"] += [] (json_value v) -> size_t
+    f["value_size"] += [] (json_value v) -> size_t
     {
       // Note: should be consistent with value_traits<json_value>::empty(),
       //       json_subscript().
@@ -129,24 +129,50 @@ namespace build2
       return 1;
     };
 
-    // $find(<json-array>, <json>)
+    // $array_size(<json-array>)
     //
-    // Return true if the JSON array contains the specified JSON value.
+    // Return the number of elements in the JSON array. If the JSON `null`
+    // value is passed instead, assume it is a missing array and return `0`.
     //
-    f["find"] += [](json_value a, value v)
+    f["array_size"] += [] (json_value a) -> size_t
     {
-      size_t i (find_index (a, move (v)));
+      if (a.type == json_type::null)
+        return 0;
+
+      if (a.type == json_type::array)
+        return a.array.size ();
+
+      fail << "expected json array instead of " << to_string (a.type) << endf;
+    };
+
+    // $array_find(<json-array>, <json>)
+    //
+    // Return true if the JSON array contains the specified JSON value. If the
+    // JSON `null` value is passed instead, assume it is a missing array and
+    // return `false`.
+    //
+    f["array_find"] += [] (json_value a, value v)
+    {
+      if (a.type == json_type::null)
+        return false;
+
+      size_t i (array_find_index (a, move (v)));
       return i != a.array.size (); // We now know it's an array.
     };
 
-    // $find_index(<json-array>, <json>)
+    // $array_find_index(<json-array>, <json>)
     //
     // Return the index of the first element in the JSON array that is equal
-    // to the specified JSON value or `$size(json-array)` if none is found.
+    // to the specified JSON value or `$array_size(<json-array>)` if none is
+    // found. If the JSON `null` value is passed instead, assume it is a
+    // missing array and return `0`.
     //
-    f["find_index"] += [](json_value a, value v)
+    f["array_find_index"] += [](json_value a, value v) -> size_t
     {
-      return find_index (a, move (v));
+      if (a.type == json_type::null)
+        return 0;
+
+      return array_find_index (a, move (v));
     };
 
 #ifndef BUILD2_BOOTSTRAP
diff --git a/tests/function/json/testscript b/tests/function/json/testscript
index fdfc9ab..9f8c2e9 100644
--- a/tests/function/json/testscript
+++ b/tests/function/json/testscript
@@ -58,13 +58,13 @@ EOO
 : size
 :
 $* <<EOI >>EOO
-print $size([json] null)
-print $size([json] true)
-print $size([json] 123)
-print $size([json] abc)
+print $value_size([json] null)
+print $value_size([json] true)
+print $value_size([json] 123)
+print $value_size([json] abc)
 print $size([string] ([json] abc)) # @@ Should be 3 (quoted, type hint).
-print $size([json] 1 2 3)
-print $size([json] one@1 two@2 three@3)
+print $value_size([json] 1 2 3)
+print $value_size([json] one@1 two@2 three@3)
 EOI
 0
 1
@@ -79,19 +79,19 @@ EOO
 :
 $* <<EOI >>EOO
 j = [json] 1 ([json] one@1 two@2) 2 true 3 null 4 abc -5 null ([json] 1 2 3)
-print $find_index($j, null)
-print $find_index($j, true)
-print $find_index($j, 3)
-print $find_index($j, 0x4)
-print $find_index($j, -5)
-print $find_index($j, abc)
-print $find_index($j, [json] 1 2 3)
-print $find_index($j, [json] two@2 one@1)
-print $find_index($j, [json] 1 2)
-print $find_index($j, [json] one@1)
-print $find_index($j, [json] one@1 two@2 three@3)
-print $find_index($j, [json] one@1 TWO@3)
-print $find_index($j, [json] one@1 two@3)
+print $array_find_index($j, null)
+print $array_find_index($j, true)
+print $array_find_index($j, 3)
+print $array_find_index($j, 0x4)
+print $array_find_index($j, -5)
+print $array_find_index($j, abc)
+print $array_find_index($j, [json] 1 2 3)
+print $array_find_index($j, [json] two@2 one@1)
+print $array_find_index($j, [json] 1 2)
+print $array_find_index($j, [json] one@1)
+print $array_find_index($j, [json] one@1 two@2 three@3)
+print $array_find_index($j, [json] one@1 TWO@3)
+print $array_find_index($j, [json] one@1 two@3)
 EOI
 5
 3
-- 
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