From 92cb088f36ab3ba24e5bb1d4b6bb8e6cbb547aaa Mon Sep 17 00:00:00 2001
From: sergeych <real.sergeych@gmail.com>
Date: Sun, 21 Dec 2025 22:49:35 +0100
Subject: [PATCH] lazy messages for check/require

---
 docs/Testing.md                                   | 15 +++++++++++++++
 lynglib/build.gradle.kts                          |  2 +-
 .../commonMain/kotlin/net/sergeych/lyng/Script.kt | 10 ++++++----
 lynglib/src/commonTest/kotlin/ScriptTest.kt       | 10 ++++++++++
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/docs/Testing.md b/docs/Testing.md
index 51ad00d..b344293 100644
--- a/docs/Testing.md
+++ b/docs/Testing.md
@@ -87,8 +87,23 @@ While not strictly for testing, these functions help in defensive programming:
 
 Throws an `IllegalArgumentException` if the condition is false. Use this for validating function arguments.
 
+If we want to evaluate the message lazily:
+
+    require(condition) { "requirement not met: %s"(someData) }
+
+In this case, formatting will only occur if the condition is not met.
+
+
+
 ### `check`
 
     check(condition, message="check failed")
 
 Throws an `IllegalStateException` if the condition is false. Use this for validating internal state.
+
+With lazy message evaluation:
+
+    check(condition) { "check failed: %s"(someData) }
+
+In this case, formatting will only occur if the condition is not met.
+
diff --git a/lynglib/build.gradle.kts b/lynglib/build.gradle.kts
index bbc4d9f..850526b 100644
--- a/lynglib/build.gradle.kts
+++ b/lynglib/build.gradle.kts
@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 group = "net.sergeych"
-version = "1.0.9-SNAPSHOT"
+version = "1.0.10-SNAPSHOT"
 
 // Removed legacy buildscript classpath declarations; plugins are applied via the plugins DSL below
 
diff --git a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
index a3df3e6..e84973c 100644
--- a/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
+++ b/lynglib/src/commonMain/kotlin/net/sergeych/lyng/Script.kt
@@ -253,16 +253,18 @@ class Script(
             addFn("require") {
                 val condition = requiredArg<ObjBool>(0)
                 if (!condition.value) {
-                    val message = args.list.getOrNull(1)?.toString() ?: "requirement not met"
-                    raiseIllegalArgument(message)
+                    var message = args.list.getOrNull(1)
+                    if( message is Statement ) message = message.execute(this)
+                    raiseIllegalArgument(message?.toString() ?: "requirement not met")
                 }
                 ObjVoid
             }
             addFn("check") {
                 val condition = requiredArg<ObjBool>(0)
                 if (!condition.value) {
-                    val message = args.list.getOrNull(1)?.toString() ?: "check failed"
-                    raiseIllegalState(message)
+                    var message = args.list.getOrNull(1)
+                    if( message is Statement ) message = message.execute(this)
+                    raiseIllegalState(message?.toString() ?: "check failed")
                 }
                 ObjVoid
             }
diff --git a/lynglib/src/commonTest/kotlin/ScriptTest.kt b/lynglib/src/commonTest/kotlin/ScriptTest.kt
index e2e0159..c3bd475 100644
--- a/lynglib/src/commonTest/kotlin/ScriptTest.kt
+++ b/lynglib/src/commonTest/kotlin/ScriptTest.kt
@@ -4297,4 +4297,14 @@ class ScriptTest {
             assertEquals(tf(...{ x: 3, y: 4, z: 50 }), "x=3, y=4, z=50")
         """.trimIndent())
     }
+
+
+//    @Test
+//    fun testSplatAssignemnt() = runTest {
+//        eval("""
+//            val abc = [1, 2, 3]
+//            val [a, b, c] = ...abc
+//            println(a, b, c)
+//        """.trimIndent())
+//    }
 }