diff --git a/src/main/kotlin/fr/postgresjson/connexion/Requester.kt b/src/main/kotlin/fr/postgresjson/connexion/Requester.kt
index 75626a4..48eeea4 100644
--- a/src/main/kotlin/fr/postgresjson/connexion/Requester.kt
+++ b/src/main/kotlin/fr/postgresjson/connexion/Requester.kt
@@ -1,5 +1,6 @@
 package fr.postgresjson.connexion
 
+import fr.postgresjson.definition.parse.parseFunction
 import fr.postgresjson.utils.searchSqlFiles
 import java.net.URI
 import fr.postgresjson.definition.Function as DefinitionFunction
@@ -48,7 +49,7 @@ class Requester(
     }
 
     fun addFunction(sql: String) {
-        DefinitionFunction(sql)
+        parseFunction(sql)
             .run { toRunnable(connection) }
             .run { functions[name] = this }
     }
diff --git a/src/main/kotlin/fr/postgresjson/definition/Function.kt b/src/main/kotlin/fr/postgresjson/definition/Function.kt
index 1998bf4..ae3ce79 100644
--- a/src/main/kotlin/fr/postgresjson/definition/Function.kt
+++ b/src/main/kotlin/fr/postgresjson/definition/Function.kt
@@ -1,345 +1,36 @@
 package fr.postgresjson.definition
 
-import fr.postgresjson.definition.Parameter.Direction
+import fr.postgresjson.definition.Parameter.Direction.IN
+import fr.postgresjson.definition.parse.ScriptPart
+import fr.postgresjson.definition.parse.trimSpace
 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 name: String,
+    override val parameters: List<Parameter>,
+    val returns: Returns,
     override val script: String,
     override val source: Path? = null,
 ): Resource, ParametersInterface {
-    /**
-     * TEXT, INT, TEXT[], CUSTOM_TYPE => String, Int, List<String>, Any;
-     * TABLE(id INT, name TEXT)       => Object { id: Int; name: String };
-     * SETOF TEXT                     => List<String>;
-     * MY_TABLE.id%TYPE               => Any;
-     * VOID                           => null;
-     */
-    val returns: Returns
-    override val name: String
-    override val parameters: List<Parameter>
 
-
-    @JvmInline
-    private value class ScriptPart(val restOfScript: String) {
-        fun copy(block: (String) -> String): ScriptPart {
-            return ScriptPart(block(restOfScript))
-        }
-
-        fun removeParentheses(): ScriptPart {
-            return if (restOfScript.take(1) == "(" && restOfScript.takeLast(1) == ")") {
-                this.copy {
-                    it.drop(1).dropLast(1)
-                }
-            } else {
-                this
-            }
-        }
-
-        fun isEmpty() = restOfScript.isEmpty()
-    }
-
-    private fun emptyScriptPart(): ScriptPart = ScriptPart("")
-
-    private class NextScript<T>(val value: T, val restOfScript: String) {
-        val nextScriptPart: ScriptPart = ScriptPart(restOfScript)
-        fun isLast() = restOfScript == ""
-        fun isEmptyValue() = value == "" || value == null
-    }
-
-    /**
-     * Return the value as ScriptPart
-     */
-    private fun NextScript<String>.valueAsScriptPart(): ScriptPart = ScriptPart(value)
-
-    init {
-        ScriptPart(script)
-            .getFunctionOrProcedure().trimSpace().nextScriptPart
-            .getFunctionName().apply { name = value }.nextScriptPart
-            .getParameters().apply { parameters = value }.nextScriptPart
-            .getReturns().apply { returns = value }
-
-    }
-
-    private fun ScriptPart.getFunctionOrProcedure(): NextScript<String> {
-        val result = """create\s+(?:or\s+replace\s+)?(procedure|function)\s+"""
-            .toRegex()
-            .find(restOfScript)
-            ?: throw FunctionNotFound()
-
-        val rest = result.range.last
-            .let { cursor -> restOfScript.drop(cursor + 1) }
-
-        return NextScript(
-            result.groups[1]!!.value,
-            rest
-        )
-    }
-
-    private fun ScriptPart.getFunctionName(): NextScript<String> {
-        try {
-            return getNextScript { status.isNotEscaped() && afterBeginBy("(", " ", "\n") }
-        } catch (e: NameMalformed) {
-            throw FunctionNameMalformed(null, e)
-        }
-    }
-
-    @OptIn(ExperimentalContracts::class)
-    private inline fun ScriptPart.change(block: String.() -> String): ScriptPart {
-        contract {
-            callsInPlace(block, EXACTLY_ONCE)
-        }
-        return ScriptPart(restOfScript.run(block))
-    }
-
-    data class Status(
-        var doubleQuoted: Boolean = false, // "
-        var simpleQuoted: Boolean = false, // '
-        var parentheses: Int = 0, // ()
-        var brackets: Int = 0, // []
-        var braces: Int = 0, // {}
-    ) {
-        fun isQuoted(): Boolean = doubleQuoted || simpleQuoted
-        fun isNotQuoted(): Boolean = !isQuoted()
-        fun isNotEscaped(): Boolean = isNotQuoted() && parentheses == 0 && brackets == 0 && braces == 0
-    }
-
-    data class Context(
-        val index: Int,
-        val currentChar: Char,
-        val status: Status,
-        val script: String,
-    ) {
-        fun afterBeginBy(vararg texts: String): Boolean = texts.any {
-            script.substring(index + 1).take(it.length) == it
-        }
-
-        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 = { false }): NextScript<String> {
-        val status = Status()
-
-        fun String.unescape(): String {
-            val first = take(1)
-            val last = takeLast(1)
-            return if (first == last && first in listOf("\"", "'")) {
-                drop(1).dropLast(1).replace("$first$first", first)
-            } else {
-                this
-            }
-        }
-
-        for ((index, c) in restOfScript.withIndex()) {
-            val nextChar = restOfScript.getOrNull(index + 1)
-            val prevChar = restOfScript.getOrNull(index - 1)
-            if (c == '"' && (nextChar != '"' && prevChar != '"')) {
-                status.doubleQuoted = !status.doubleQuoted
-            } else if (c == '\'' && (nextChar != '\'' && prevChar != '\'')) {
-                status.simpleQuoted = !status.simpleQuoted
-            } else if (c == '(' && status.isNotQuoted()) {
-                status.parentheses++
-            } else if (c == ')' && status.isNotQuoted()) {
-                status.parentheses--
-            } else if (c == '[' && status.isNotQuoted()) {
-                status.brackets++
-            } else if (c == ']' && status.isNotQuoted()) {
-                status.brackets--
-            } else if (c == '{' && status.isNotQuoted()) {
-                status.braces++
-            } else if (c == '}' && status.isNotQuoted()) {
-                status.braces--
-            }
-
-            if (isEnd(Context(index, c, status.copy(), restOfScript))) {
-                return NextScript(restOfScript.take(index + 1).unescape(), restOfScript.drop(index + 1))
-            }
-        }
-        if (status.isNotEscaped()) {
-            return NextScript(restOfScript.unescape().trim(), "").trimSpace()
-        }
-        throw ParseError()
-    }
-
-    private fun ScriptPart.split(delimiter: String): List<ScriptPart> {
-        val parts: MutableList<ScriptPart> = mutableListOf()
-        var rest: ScriptPart = this
-        do {
-            rest = rest.trimSpace()
-                .getNextScript { status.isNotEscaped() && currentChar.toString() == delimiter }
-                .trimSpace()
-                .also { parts.add(it.valueAsScriptPart().trimSpace().trimEnd(',')) }
-                .nextScriptPart
-        } while (!rest.isEmpty())
-
-        return parts
-    }
-
-    private fun ScriptPart.getNextInteger(): NextScript<Int?> {
-        val trimmed = restOfScript.trimStart { !it.isDigit() }
-        val digits = trimmed.takeWhile { it.isDigit() }
-        val restOfScript = trimmed.trimStart { it.isDigit() }
-        return NextScript(digits.toIntOrNull(), restOfScript).trimSpace()
-    }
-
-    private fun ScriptPart.getParameters(): NextScript<List<Parameter>> {
-        val allParametersScript = this.getNextScript {
-            currentChar == ')' && status.isNotEscaped()
-        }
-        val parameterList: List<Parameter> = allParametersScript
-            .valueAsScriptPart()
-            .removeParentheses()
-            .split(",")
-            .map { it.toParameter() }
-
-        return NextScript(parameterList, allParametersScript.restOfScript)
-    }
-
-    private fun ScriptPart.trimSpace(): ScriptPart {
-        for ((n, char) in restOfScript.withIndex()) {
-            if (char !in listOf(' ', '\n', '\t')) {
-                return ScriptPart(
-                    restOfScript.drop(n)
-                )
-            }
-        }
-        return ScriptPart(restOfScript)
-    }
-
-    private fun <T> NextScript<T>.trimSpace(): NextScript<T> {
-        val spaces = charArrayOf(' ', '\n', '\t')
-        return trim(chars = spaces)
-    }
-
-    private fun ScriptPart.trimEnd(vararg chars: Char): ScriptPart {
-        return this.change { dropLastWhile { it in chars } }
-    }
-
-    private fun <T> NextScript<T>.trim(vararg chars: Char): NextScript<T> {
-        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.toParameter(): Parameter {
-        var script: ScriptPart = this.trimSpace()
-        return Parameter(
-            direction = script.getParameterMode().apply { script = nextScriptPart }.value,
-            name = script.getParameterName().trimSpace().apply { script = nextScriptPart }.value.trim(),
-            type = script.getParameterType().trimSpace().apply { script = nextScriptPart }.value,
-            default = script.getParameterDefault().trimSpace().apply { script = nextScriptPart }.value,
-        )
-    }
-
-    private fun ScriptPart.getParameterMode(): NextScript<Direction> {
-        return when {
-            restOfScript.startsWith("inout ", true) -> NextScript(Direction.INOUT, restOfScript.drop("inout ".length))
-            restOfScript.startsWith("in ", true) -> NextScript(Direction.IN, restOfScript.drop("in ".length))
-            restOfScript.startsWith("out ", true) -> NextScript(Direction.OUT, restOfScript.drop("out ".length))
-            else -> NextScript(Direction.IN, restOfScript)
-        }
-    }
-
-    private fun ScriptPart.getParameterName(): NextScript<String> {
-        try {
-            return getNextScript { afterBeginBy(" ", "\n") }
-        } catch (e: NameMalformed) {
-            throw ParameterNameMalformed(null, e)
-        }
-    }
-
-    private fun ScriptPart.getParameterType(): NextScript<ParameterType> {
-        val fullType = try {
-            val endTextList = arrayOf(" default ", "=", ")")
-            getNextScript { afterBeginBy(texts = endTextList) }
-        } catch (e: ParseError) {
-            throw ParameterTypeMalformed(null, e)
-        }
-
-        var rest: ScriptPart = fullType.valueAsScriptPart()
-
-        val name = rest
-            .getNextScript { afterBeginBy("(") }
-            .apply { rest = nextScriptPart }
-        val precision = rest
-            .getNextInteger()
-            .apply { rest = nextScriptPart }
-        val scale = rest
-            .getNextInteger()
-            .apply { rest = nextScriptPart }
-
-        return NextScript(
-            ParameterType(
-                name = name.value.trim(),
-                precision = precision.value,
-                scale = scale.value
-            ), fullType.nextScriptPart.restOfScript
-        )
-    }
-
-    private fun ScriptPart.getParameterDefault(): NextScript<String?> {
-        return if (this.isEmpty() || this.restOfScript == ")") {
-            NextScript(null, "")
-        } else {
-            """^(\s*=\s*|\s+default\s+)(.+)\s*$"""
-                .toRegex(IGNORE_CASE)
-                .find(restOfScript)
-                .let { it ?: throw ParameterDefaultMalformed() }
-                .let { it.groups[2]!!.value }
-                .let { NextScript(it, "") }
-        }
-    }
-
-    /**
-     * TODO Finalize this
-     */
-    private fun ScriptPart.getReturns(): NextScript<Returns> {
-        return NextScript(Returns.Void(), "")
-    }
-
-    class FunctionNotFound(cause: Throwable? = null): Resource.ParseException("Function not found in script", cause)
-    class ParameterNotFound(cause: Throwable? = null): Resource.ParseException("Parameter not found in script", cause)
-    class FunctionNameMalformed(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Function name is malformed", cause)
-
-    class ParameterNameMalformed(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Parameter name is malformed", cause)
-
-    class ParameterTypeMalformed(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Parameter type is malformed", cause)
-
-    class ParameterDefaultMalformed(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Parameter default is malformed", cause)
-
-    class NameMalformed(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Name is malformed", cause)
-
-    class ParseError(message: String? = null, cause: Throwable? = null):
-        Resource.ParseException(message ?: "Parsing fail", cause)
+//    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) }
+//        }
+//    }
 
     fun getDefinition(): String = parameters
-        .filter { it.direction == Direction.IN }
+        .filter { it.direction == IN }
         .joinToString(", ") { it.type.toString() }
         .let { "$name ($it)" }
 
@@ -356,44 +47,4 @@ class Function(
     infix fun `is different from`(other: Function): Boolean {
         return other.script != this.script
     }
-
-    sealed class Returns(
-        val definition: String,
-        val isSetOf: Boolean,
-    ) {
-        class Primitive(
-            definition: String,
-            isSetOf: Boolean,
-        ): Returns(definition, isSetOf) {
-            val name = definition
-                .trim('"')
-        }
-
-        class PrimitiveList(
-            definition: String,
-            isSetOf: Boolean,
-        ): Returns(definition, isSetOf) {
-            val name = definition
-                .drop(2)
-                .trim('"')
-        }
-
-        class Table(
-            definition: String,
-            isSetOf: Boolean,
-            val parameters: List<ParameterTable>,
-        ): Returns(definition, isSetOf) {
-            class ParameterTable(
-                override val name: String,
-                override val type: ParameterType,
-            ): ParameterSimpleI
-        }
-
-        class Any(
-            isSetOf: Boolean,
-        ): Returns("any", isSetOf)
-
-        class Void: Returns("void", false)
-    }
-
 }
diff --git a/src/main/kotlin/fr/postgresjson/definition/Resource.kt b/src/main/kotlin/fr/postgresjson/definition/Resource.kt
index 4a96a9b..8241803 100644
--- a/src/main/kotlin/fr/postgresjson/definition/Resource.kt
+++ b/src/main/kotlin/fr/postgresjson/definition/Resource.kt
@@ -1,5 +1,6 @@
 package fr.postgresjson.definition
 
+import fr.postgresjson.definition.parse.parseFunction
 import java.io.File
 import java.net.URL
 import java.nio.file.Path
@@ -23,7 +24,7 @@ sealed interface Resource {
                 Migration(resource, path)
             } catch (e: ParseException) {
                 try {
-                    Function(resource, path)
+                    parseFunction(resource, path)
                 } catch (e: ParseException) {
                     try {
                         Query(resource, path)
diff --git a/src/main/kotlin/fr/postgresjson/definition/Returns.kt b/src/main/kotlin/fr/postgresjson/definition/Returns.kt
new file mode 100644
index 0000000..a9900da
--- /dev/null
+++ b/src/main/kotlin/fr/postgresjson/definition/Returns.kt
@@ -0,0 +1,40 @@
+package fr.postgresjson.definition
+
+sealed class Returns(
+    val definition: String,
+    val isSetOf: Boolean,
+) {
+    class Primitive(
+        definition: String,
+        isSetOf: Boolean,
+    ): Returns(definition, isSetOf) {
+        val name = definition
+            .trim('"')
+    }
+
+    class PrimitiveList(
+        definition: String,
+        isSetOf: Boolean,
+    ): Returns(definition, isSetOf) {
+        val name = definition
+            .drop(2)
+            .trim('"')
+    }
+
+    class Table(
+        definition: String,
+        isSetOf: Boolean,
+        val parameters: List<ParameterTable>,
+    ): Returns(definition, isSetOf) {
+        class ParameterTable(
+            override val name: String,
+            override val type: ParameterType,
+        ): ParameterSimpleI
+    }
+
+    class Any(
+        isSetOf: Boolean,
+    ): Returns("any", isSetOf)
+
+    class Void: Returns("void", false)
+}
\ No newline at end of file
diff --git a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt
new file mode 100644
index 0000000..dd59ae6
--- /dev/null
+++ b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingFunction.kt
@@ -0,0 +1,160 @@
+package fr.postgresjson.definition.parse
+
+import fr.postgresjson.definition.Function
+import fr.postgresjson.definition.Parameter
+import fr.postgresjson.definition.Returns.Void
+import fr.postgresjson.definition.Parameter.Direction
+import fr.postgresjson.definition.Parameter.Direction.IN
+import fr.postgresjson.definition.Parameter.Direction.INOUT
+import fr.postgresjson.definition.Parameter.Direction.OUT
+import fr.postgresjson.definition.ParameterType
+import fr.postgresjson.definition.Resource.ParseException
+import fr.postgresjson.definition.Returns
+import java.nio.file.Path
+import kotlin.text.RegexOption.IGNORE_CASE
+
+internal fun parseFunction(script: String, source: Path? = null): Function {
+    val name: String
+    val parameters: List<Parameter>
+    val returns: Returns
+    ScriptPart(script)
+        .getFunctionOrProcedure().trimSpace().nextScriptPart
+        .getFunctionName().apply { name = value }.nextScriptPart
+        .getParameters().apply { parameters = value }.nextScriptPart
+        .getReturns().apply { returns = value }
+
+    return Function(name, parameters, returns, script, source)
+}
+
+
+@Throws(FunctionNameMalformed::class)
+internal fun ScriptPart.getFunctionName(): NextScript<String> {
+    try {
+        return getNextScript { status.isNotEscaped() && afterBeginBy("(", " ", "\n") }
+    } catch (e: ParseException) {
+        throw FunctionNameMalformed(this, e)
+    }
+}
+internal class FunctionNameMalformed(val script: ScriptPart, cause: Throwable? = null):
+    ParseException("Function name is malformed", cause)
+
+@Throws(FunctionNotFound::class)
+internal fun ScriptPart.getFunctionOrProcedure(): NextScript<String> {
+    val result = """create\s+(?:or\s+replace\s+)?(procedure|function)\s+"""
+        .toRegex()
+        .find(restOfScript)
+        ?: throw FunctionNotFound(this)
+
+    val rest = result.range.last
+        .let { cursor -> restOfScript.drop(cursor + 1) }
+
+    return NextScript(
+        result.groups[1]!!.value,
+        rest
+    )
+}
+
+internal class FunctionNotFound(val script: ScriptPart):
+    ParseException("Function not found in script")
+
+internal fun ScriptPart.getParameters(): NextScript<List<Parameter>> {
+    val allParametersScript = this.getNextScript {
+        currentChar == ')' && status.isNotEscaped()
+    }
+    val parameterList: List<Parameter> = allParametersScript
+        .valueAsScriptPart()
+        .removeParentheses()
+        .split(",")
+        .map { it.toParameter() }
+
+    return NextScript(parameterList, allParametersScript.restOfScript)
+}
+
+private fun ScriptPart.toParameter(): Parameter {
+    var script: ScriptPart = this.trimSpace()
+    return Parameter(
+        direction = script.getParameterMode().apply { script = nextScriptPart }.value,
+        name = script.getParameterName().trimSpace().apply { script = nextScriptPart }.value.trim(),
+        type = script.getParameterType().trimSpace().apply { script = nextScriptPart }.value,
+        default = script.getParameterDefault().trimSpace().apply { script = nextScriptPart }.value,
+    )
+}
+private fun ScriptPart.getParameterMode(): NextScript<Direction> {
+    return when {
+        restOfScript.startsWith("inout ", true) -> NextScript(INOUT, restOfScript.drop("inout ".length))
+        restOfScript.startsWith("in ", true) -> NextScript(IN, restOfScript.drop("in ".length))
+        restOfScript.startsWith("out ", true) -> NextScript(OUT, restOfScript.drop("out ".length))
+        else -> NextScript(IN, restOfScript)
+    }
+}
+
+@Throws(ParameterNameMalformed::class)
+private fun ScriptPart.getParameterName(): NextScript<String> {
+    try {
+        return getNextScript { afterBeginBy(" ", "\n") }
+    } catch (e: ParseException) {
+        throw ParameterNameMalformed(this, e)
+    }
+}
+private class ParameterNameMalformed(val script: ScriptPart, cause: Throwable):
+    ParseException("Parameter name is malformed", cause)
+
+@Throws(ParameterTypeMalformed::class)
+private fun ScriptPart.getParameterType(): NextScript<ParameterType> {
+    val fullType = try {
+        val endTextList = arrayOf(" default ", "=", ")")
+        getNextScript { afterBeginBy(texts = endTextList) }
+    } catch (e: ParseError) {
+        throw ParameterTypeMalformed(this, e)
+    }
+
+    var rest: ScriptPart = fullType.valueAsScriptPart()
+
+    val name = rest
+        .getNextScript { afterBeginBy("(") }
+        .apply { rest = nextScriptPart }
+    val precision = rest
+        .getNextInteger()
+        .apply { rest = nextScriptPart }
+    val scale = rest
+        .getNextInteger()
+        .apply { rest = nextScriptPart }
+
+    return NextScript(
+        ParameterType(
+            name = name.value.trim(),
+            precision = precision.value,
+            scale = scale.value
+        ), fullType.nextScriptPart.restOfScript
+    )
+}
+
+internal class ParameterTypeMalformed(val script: ScriptPart, cause: Throwable):
+    ParseException("Parameter type is malformed", cause)
+
+@Throws(ParameterDefaultMalformed::class)
+private fun ScriptPart.getParameterDefault(): NextScript<String?> {
+    return if (this.isEmpty() || this.restOfScript == ")") {
+        NextScript(null, "")
+    } else {
+        """^(\s*=\s*|\s+default\s+)(.+)\s*$"""
+            .toRegex(IGNORE_CASE)
+            .find(restOfScript)
+            .let { it ?: throw ParameterDefaultMalformed(this) }
+            .let { it.groups[2]!!.value }
+            .let { NextScript(it, "") }
+    }
+}
+
+private class ParameterDefaultMalformed(val script: ScriptPart):
+    ParseException("Parameter default is malformed")
+
+/**
+ * TODO Finalize this
+ */
+internal fun ScriptPart.getReturns(): NextScript<Returns> {
+    return NextScript(Void(), "")
+}
+
+class ParseError(message: String? = null, cause: Throwable? = null):
+    ParseException(message ?: "Parsing fail", cause)
\ No newline at end of file
diff --git a/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt
new file mode 100644
index 0000000..74d7333
--- /dev/null
+++ b/src/main/kotlin/fr/postgresjson/definition/parse/ParsingHelper.kt
@@ -0,0 +1,164 @@
+package fr.postgresjson.definition.parse
+
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.InvocationKind.EXACTLY_ONCE
+import kotlin.contracts.contract
+
+@JvmInline
+internal value class ScriptPart(val restOfScript: String) {
+    fun copy(block: (String) -> String): ScriptPart {
+        return ScriptPart(block(restOfScript))
+    }
+
+    fun isEmpty() = restOfScript.isEmpty()
+}
+
+internal class NextScript<T>(val value: T, val restOfScript: String) {
+    val nextScriptPart: ScriptPart = ScriptPart(restOfScript)
+    fun isLast() = restOfScript == ""
+    fun isEmptyValue() = value == "" || value == null
+}
+
+internal fun ScriptPart.removeParentheses(): ScriptPart {
+    return if (restOfScript.take(1) == "(" && restOfScript.takeLast(1) == ")") {
+        this.copy {
+            it.drop(1).dropLast(1)
+        }
+    } else {
+        this
+    }
+}
+/**
+ * Get next part of script.
+ * You can define a list of characters that end the part of script. Like `(` or space.
+ */
+@Throws(ParseError::class)
+internal fun ScriptPart.getNextScript(isEnd: Context.() -> Boolean = { false }): NextScript<String> {
+    val status = Status()
+
+    fun String.unescape(): String {
+        val first = take(1)
+        val last = takeLast(1)
+        return if (first == last && first in listOf("\"", "'")) {
+            drop(1).dropLast(1).replace("$first$first", first)
+        } else {
+            this
+        }
+    }
+
+    for ((index, c) in restOfScript.withIndex()) {
+        val nextChar = restOfScript.getOrNull(index + 1)
+        val prevChar = restOfScript.getOrNull(index - 1)
+        if (c == '"' && (nextChar != '"' && prevChar != '"')) {
+            status.doubleQuoted = !status.doubleQuoted
+        } else if (c == '\'' && (nextChar != '\'' && prevChar != '\'')) {
+            status.simpleQuoted = !status.simpleQuoted
+        } else if (c == '(' && status.isNotQuoted()) {
+            status.parentheses++
+        } else if (c == ')' && status.isNotQuoted()) {
+            status.parentheses--
+        } else if (c == '[' && status.isNotQuoted()) {
+            status.brackets++
+        } else if (c == ']' && status.isNotQuoted()) {
+            status.brackets--
+        } else if (c == '{' && status.isNotQuoted()) {
+            status.braces++
+        } else if (c == '}' && status.isNotQuoted()) {
+            status.braces--
+        }
+
+        if (isEnd(Context(index, c, status.copy(), restOfScript))) {
+            return NextScript(restOfScript.take(index + 1).unescape(), restOfScript.drop(index + 1))
+        }
+    }
+    if (status.isNotEscaped()) {
+        return NextScript(restOfScript.unescape().trim(), "").trimSpace()
+    }
+    throw ParseError()
+}
+
+internal fun <T> NextScript<T>.trimSpace(): NextScript<T> {
+    val spaces = charArrayOf(' ', '\n', '\t')
+    return trim(chars = spaces)
+}
+
+internal fun ScriptPart.trimSpace(): ScriptPart {
+    for ((n, char) in restOfScript.withIndex()) {
+        if (char !in listOf(' ', '\n', '\t')) {
+            return ScriptPart(
+                restOfScript.drop(n)
+            )
+        }
+    }
+    return ScriptPart(restOfScript)
+}
+
+internal fun <T> NextScript<T>.trim(vararg chars: Char): NextScript<T> {
+    return NextScript(value, restOfScript.apply { dropWhile { it in chars } })
+}
+
+internal fun ScriptPart.trimEnd(vararg chars: Char): ScriptPart {
+    return this.change { dropLastWhile { it in chars } }
+}
+
+internal fun ScriptPart.split(delimiter: String): List<ScriptPart> {
+    val parts: MutableList<ScriptPart> = mutableListOf()
+    var rest: ScriptPart = this
+    do {
+        rest = rest.trimSpace()
+            .getNextScript { status.isNotEscaped() && currentChar.toString() == delimiter }
+            .trimSpace()
+            .also { parts.add(it.valueAsScriptPart().trimSpace().trimEnd(',')) }
+            .nextScriptPart
+    } while (!rest.isEmpty())
+
+    return parts
+}
+
+/**
+ * Return the value as ScriptPart
+ */
+internal fun NextScript<String>.valueAsScriptPart(): ScriptPart = ScriptPart(value)
+
+@OptIn(ExperimentalContracts::class)
+internal inline fun ScriptPart.change(block: String.() -> String): ScriptPart {
+    contract {
+        callsInPlace(block, EXACTLY_ONCE)
+    }
+    return ScriptPart(restOfScript.run(block))
+}
+
+
+internal fun ScriptPart.getNextInteger(): NextScript<Int?> {
+    val trimmed = restOfScript.trimStart { !it.isDigit() }
+    val digits = trimmed.takeWhile { it.isDigit() }
+    val restOfScript = trimmed.trimStart { it.isDigit() }
+    return NextScript(digits.toIntOrNull(), restOfScript).trimSpace()
+}
+
+
+
+internal data class Status(
+    var doubleQuoted: Boolean = false, // "
+    var simpleQuoted: Boolean = false, // '
+    var parentheses: Int = 0, // ()
+    var brackets: Int = 0, // []
+    var braces: Int = 0, // {}
+) {
+    fun isQuoted(): Boolean = doubleQuoted || simpleQuoted
+    fun isNotQuoted(): Boolean = !isQuoted()
+    fun isNotEscaped(): Boolean = isNotQuoted() && parentheses == 0 && brackets == 0 && braces == 0
+}
+
+internal data class Context(
+    val index: Int,
+    val currentChar: Char,
+    val status: Status,
+    val script: String,
+) {
+    fun afterBeginBy(vararg texts: String): Boolean = texts.any {
+        script.substring(index + 1).take(it.length) == it
+    }
+
+    val nextChar: Char? get() = script.substring(index + 1).getOrNull(0)
+}
\ No newline at end of file
diff --git a/src/main/kotlin/fr/postgresjson/functionGenerator/FunctionGenerator.kt b/src/main/kotlin/fr/postgresjson/functionGenerator/FunctionGenerator.kt
index d11eea0..b2a3f6b 100644
--- a/src/main/kotlin/fr/postgresjson/functionGenerator/FunctionGenerator.kt
+++ b/src/main/kotlin/fr/postgresjson/functionGenerator/FunctionGenerator.kt
@@ -1,8 +1,7 @@
 package fr.postgresjson.functionGenerator
 
-import com.github.jasync.sql.db.util.length
 import fr.postgresjson.definition.Function
-import fr.postgresjson.definition.Function.Returns
+import fr.postgresjson.definition.Returns
 import fr.postgresjson.definition.Parameter
 import fr.postgresjson.definition.Parameter.Direction.IN
 import fr.postgresjson.definition.Parameter.Direction.INOUT
diff --git a/src/main/kotlin/fr/postgresjson/migration/Function.kt b/src/main/kotlin/fr/postgresjson/migration/Function.kt
index 1527174..d996ce5 100644
--- a/src/main/kotlin/fr/postgresjson/migration/Function.kt
+++ b/src/main/kotlin/fr/postgresjson/migration/Function.kt
@@ -3,6 +3,7 @@ package fr.postgresjson.migration
 import com.github.jasync.sql.db.postgresql.exceptions.GenericDatabaseException
 import fr.postgresjson.connexion.Connection
 import fr.postgresjson.connexion.execute
+import fr.postgresjson.definition.parse.parseFunction
 import fr.postgresjson.migration.Migration.Action
 import fr.postgresjson.migration.Migration.Status
 import java.util.Date
@@ -30,8 +31,8 @@ data class Function(
         connection: Connection,
         executedAt: Date? = null
     ) : this(
-        DefinitionFunction(up),
-        DefinitionFunction(down),
+        parseFunction(up),
+        parseFunction(down),
         connection,
         executedAt
     )
diff --git a/src/main/kotlin/fr/postgresjson/migration/MigrationExecutor.kt b/src/main/kotlin/fr/postgresjson/migration/MigrationExecutor.kt
index 1f6d4bf..86ce475 100644
--- a/src/main/kotlin/fr/postgresjson/migration/MigrationExecutor.kt
+++ b/src/main/kotlin/fr/postgresjson/migration/MigrationExecutor.kt
@@ -2,6 +2,7 @@ package fr.postgresjson.migration
 
 import com.fasterxml.jackson.core.type.TypeReference
 import fr.postgresjson.connexion.Connection
+import fr.postgresjson.definition.parse.parseFunction
 import fr.postgresjson.migration.Migration.Action
 import fr.postgresjson.migration.Migration.Status
 import fr.postgresjson.utils.LoggerDelegate
@@ -147,7 +148,7 @@ class MigrationExecutor private constructor(
     }
 
     fun addFunction(sql: String): MigrationExecutor {
-        addFunction(DefinitionFunction(sql))
+        addFunction(parseFunction(sql))
         return this
     }
 
diff --git a/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt b/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
index 703f959..f999826 100644
--- a/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
+++ b/src/test/kotlin/fr/postgresjson/definition/FunctionTest.kt
@@ -1,5 +1,6 @@
 package fr.postgresjson.definition
 
+import fr.postgresjson.definition.parse.parseFunction
 import io.kotest.core.spec.style.FreeSpec
 import io.kotest.matchers.collections.shouldHaveSize
 import io.kotest.matchers.shouldBe
@@ -7,7 +8,7 @@ import io.kotest.matchers.shouldBe
 class FunctionTest: FreeSpec({
     "Function name" - {
         "all in lower" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun() returns text language plpgsql as
@@ -19,7 +20,7 @@ class FunctionTest: FreeSpec({
         }
 
         "first letter caps" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function Myfun() returns text language plpgsql as
@@ -31,7 +32,7 @@ class FunctionTest: FreeSpec({
         }
 
         "with numbers" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun001() returns text language plpgsql as
@@ -43,7 +44,7 @@ class FunctionTest: FreeSpec({
         }
 
         "escaped name with space" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function "My fun"() returns text language plpgsql as
@@ -55,7 +56,7 @@ class FunctionTest: FreeSpec({
         }
 
         "escaped name with double quote in name" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function "My""fun" () returns text language plpgsql as
@@ -67,7 +68,7 @@ class FunctionTest: FreeSpec({
         }
 
         "name with new line before and after" {
-            Function(
+            parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function 
@@ -85,7 +86,7 @@ class FunctionTest: FreeSpec({
 
     "Parameters" - {
         "One parameter text" - {
-            val param = Function(
+            val param = parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun(one text) returns text language plpgsql as
@@ -107,7 +108,7 @@ class FunctionTest: FreeSpec({
         }
 
         "Two parameters" - {
-            val param = Function(
+            val param = parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun(one text, two int) returns text language plpgsql as
@@ -131,7 +132,7 @@ class FunctionTest: FreeSpec({
         }
 
         "parameters with `character varying(255)`" - {
-            val param = Function(
+            val param = parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun(one character varying(255)) returns text language plpgsql as
@@ -158,7 +159,7 @@ class FunctionTest: FreeSpec({
         }
 
         "parameters with `numeric(16, 8)`" - {
-            val param = Function(
+            val param = parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun(one numeric(16, 8)) returns text language plpgsql as
@@ -188,7 +189,7 @@ class FunctionTest: FreeSpec({
         }
 
         "parameters with default text" - {
-            val param = Function(
+            val param = parseFunction(
                 // language=PostgreSQL
                 """
                 create or replace function myfun(one text default 'example') returns text language plpgsql as
diff --git a/src/test/kotlin/fr/postgresjson/functionGenerator/FunctionGeneratorTest.kt b/src/test/kotlin/fr/postgresjson/functionGenerator/FunctionGeneratorTest.kt
index 8590080..e6f4bf3 100644
--- a/src/test/kotlin/fr/postgresjson/functionGenerator/FunctionGeneratorTest.kt
+++ b/src/test/kotlin/fr/postgresjson/functionGenerator/FunctionGeneratorTest.kt
@@ -1,6 +1,6 @@
 package fr.postgresjson.functionGenerator
 
-import fr.postgresjson.definition.Function
+import fr.postgresjson.definition.parse.parseFunction
 import io.kotest.core.Tag
 import io.kotest.core.spec.style.StringSpec
 import org.amshove.kluent.`should be equal to`
@@ -34,7 +34,7 @@ class FunctionGeneratorTest : StringSpec({
             |}
         """.trimMargin()
 
-        generator.generate(Function(functionSql)) `should be equal to` expectedGenerated
+        generator.generate(parseFunction(functionSql)) `should be equal to` expectedGenerated
     }
 
     "generate function with return void" {
@@ -60,7 +60,7 @@ class FunctionGeneratorTest : StringSpec({
             |}
         """.trimMargin()
 
-        generator.generate(Function(functionSql)) `should be equal to` expectedGenerated
+        generator.generate(parseFunction(functionSql)) `should be equal to` expectedGenerated
     }
 
     "generate function with multiple args and defaults" {
@@ -90,6 +90,6 @@ class FunctionGeneratorTest : StringSpec({
             |}
         """.trimMargin()
 
-        generator.generate(Function(functionSql)) `should be equal to` expectedGenerated
+        generator.generate(parseFunction(functionSql)) `should be equal to` expectedGenerated
     }
 })