Implement getArgDefault

src/main/kotlin/fr/postgresjson/definition/Function.kt

@@ -1,11 +1,11 @@
 package fr.postgresjson.definition
 
-import com.github.jasync.sql.db.util.length
 import fr.postgresjson.definition.Parameter.Direction
 import java.nio.file.Path
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind.EXACTLY_ONCE
 import kotlin.contracts.contract
+import kotlin.text.RegexOption.IGNORE_CASE
 
 class Function(
     override val script: String,
@@ -46,6 +46,8 @@ class Function(
 
     private class NextScript<T>(val value: T, val restOfScript: String) {
         val nextScriptPart: ScriptPart = ScriptPart(restOfScript)
+        fun isLast() = restOfScript == ""
+        fun isEmptyValue() = value == "" || value == null
     }
 
     /**
@@ -79,7 +81,7 @@ class Function(
 
     private fun ScriptPart.getFunctionName(): NextScript<String> {
         try {
-            return getNextScript { status.isNotEscaped() && listOf("(", " ", "\n").any { afterBeginBy(it) } }
+            return getNextScript { status.isNotEscaped() && afterBeginBy("(", " ", "\n") }
         } catch (e: NameMalformed) {
             throw FunctionNameMalformed(null, e)
         }
@@ -112,17 +114,17 @@ class Function(
         val script: String,
     ) {
         fun afterBeginBy(vararg texts: String): Boolean = texts.any {
-            script.substring(index+1).take(it.length) == it
+            script.substring(index + 1).take(it.length) == it
         }
 
-        val nextChar: Char? get() = script.substring(index+1).getOrNull(0)
+        val nextChar: Char? get() = script.substring(index + 1).getOrNull(0)
     }
 
     /**
      * Get next part of script.
      * You can define a list of characters that end the part of script. Like `(` or space.
      */
-    private fun ScriptPart.getNextScript(isEnd: Context.() -> Boolean): NextScript<String> {
+    private fun ScriptPart.getNextScript(isEnd: Context.() -> Boolean = { false }): NextScript<String> {
         val status = Status()
 
         fun String.unescape(): String {
@@ -157,7 +159,7 @@ class Function(
             }
 
             if (isEnd(Context(index, c, status.copy(), restOfScript))) {
-                return NextScript(restOfScript.take(index+1).unescape(), restOfScript.drop(index+1))
+                return NextScript(restOfScript.take(index + 1).unescape(), restOfScript.drop(index + 1))
             }
         }
         if (status.isNotEscaped()) {
@@ -224,6 +226,22 @@ class Function(
         return NextScript(value, restOfScript.apply { dropWhile { it in chars } })
     }
 
+    private fun <T> NextScript<T>.changeValue(block: (T) -> T): NextScript<T> {
+        return NextScript(block(value), restOfScript)
+    }
+
+    private fun <T> NextScript<T>.changeScript(block: (String) -> String): NextScript<T> {
+        return NextScript(value, block(restOfScript))
+    }
+
+    private fun <T> NextScript<T>.dropOneOf(vararg endTextList: String): NextScript<T> {
+        return changeScript { script ->
+            endTextList
+                .filter { script.startsWith(it) }
+                .let { script.drop(it.size) }
+        }
+    }
+
     private fun ScriptPart.toArgument(): Parameter {
         var script: ScriptPart = this.trimSpace()
         return Parameter(
@@ -245,10 +263,7 @@ class Function(
 
     private fun ScriptPart.getArgName(): NextScript<String> {
         try {
-            return getNextScript {
+            return getNextScript { afterBeginBy(" ", "\n") }
-                listOf(" ", "\n")
-                    .any { afterBeginBy(it) }
-            }
         } catch (e: NameMalformed) {
             throw ArgNameMalformed(null, e)
         }
@@ -256,10 +271,8 @@ class Function(
 
     private fun ScriptPart.getArgType(): NextScript<ArgumentType> {
         val fullType = try {
-            getNextScript {
+            val endTextList = arrayOf(" default ", "=", ")")
-                listOf(" default ", "=", ")")
+            getNextScript { afterBeginBy(texts = endTextList) }
-                    .any { afterBeginBy(it) }
-            }
         } catch (e: ParseError) {
             throw ArgTypeMalformed(null, e)
         }
@@ -285,11 +298,17 @@ class Function(
         )
     }
 
-    /**
-     * TODO implement this method
-     */
     private fun ScriptPart.getArgDefault(): NextScript<String?> {
-        return NextScript("plop", "")
+        return if (this.isEmpty() || this.restOfScript == ")") {
+            NextScript(null, "")
+        } else {
+            """^(\s*=\s*|\s+default\s+)(.+)\s*$"""
+                .toRegex(IGNORE_CASE)
+                .find(restOfScript)
+                .let { it ?: throw ArgDefaultMalformed() }
+                .let { it.groups[2]!!.value }
+                .let { NextScript(it, "") }
+        }
     }
 
     /**
@@ -303,11 +322,16 @@ class Function(
     class ArgumentNotFound(cause: Throwable? = null): Resource.ParseException("Argument not found in script", cause)
     class FunctionNameMalformed(message: String? = null, cause: Throwable? = null):
         Resource.ParseException(message ?: "Function name is malformed", cause)
+
     class ArgNameMalformed(message: String? = null, cause: Throwable? = null):
         Resource.ParseException(message ?: "Arg name is malformed", cause)
+
     class ArgTypeMalformed(message: String? = null, cause: Throwable? = null):
         Resource.ParseException(message ?: "Arg type is malformed", cause)
 
+    class ArgDefaultMalformed(message: String? = null, cause: Throwable? = null):
+        Resource.ParseException(message ?: "Arg default is malformed", cause)
+
     class NameMalformed(message: String? = null, cause: Throwable? = null):
         Resource.ParseException(message ?: "name is malformed", cause)
 

src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt

@@ -186,6 +186,32 @@ class FunctionTest: FreeSpec({
                 param[0].type.scale shouldBe 8
             }
         }
+
+        "parameters with default text" - {
+            val param = Function(
+                // language=PostgreSQL
+                """
+                create or replace function myfun(one text default 'example') returns text language plpgsql as
+                $$ begin end;$$;
+                """.trimIndent()
+            ).parameters
+
+            "should have 1 parameters" {
+                param shouldHaveSize 1
+            }
+
+            "should have name" {
+                param[0].name shouldBe "one"
+            }
+
+            "should have type name" {
+                param[0].type.name shouldBe "text"
+            }
+
+            "should have default text" {
+                param[0].default shouldBe "'example'"
+            }
+        }
     }
 
 //    "function returns" - {