diff --git a/config/datatype/builtin/any.go b/config/datatype/builtin/any.go
new file mode 100644
index 0000000..5e3cc94
--- /dev/null
+++ b/config/datatype/builtin/any.go
@@ -0,0 +1,17 @@
+package builtin
+
+import "git.xdrm.io/go/aicra/config/datatype"
+
+// AnyDataType is what its name tells
+type AnyDataType struct{}
+
+// Build returns the validator
+func (AnyDataType) Build(typeName string) datatype.Validator {
+	// nothing if type not handled
+	if typeName != "any" {
+		return nil
+	}
+	return func(value interface{}) (interface{}, bool) {
+		return value, true
+	}
+}
diff --git a/typecheck/builtin/any_test.go b/config/datatype/builtin/any_test.go
similarity index 67%
rename from typecheck/builtin/any_test.go
rename to config/datatype/builtin/any_test.go
index de4f260..4c3678e 100644
--- a/typecheck/builtin/any_test.go
+++ b/config/datatype/builtin/any_test.go
@@ -4,26 +4,13 @@ import (
 	"fmt"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestAny_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewAny())
-
-	switch cast := inst.(type) {
-	case *builtin.Any:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.Any{}, cast)
-	}
-}
-
 func TestAny_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewAny()
+	dt := builtin.AnyDataType{}
 
 	tests := []struct {
 		Type    string
@@ -39,9 +26,9 @@ func TestAny_AvailableTypes(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		checker := inst.Checker(test.Type)
+		validator := dt.Build(test.Type)
 
-		if checker == nil {
+		if validator == nil {
 			if test.Handled {
 				t.Errorf("expect %q to be handled", test.Type)
 			}
@@ -60,8 +47,8 @@ func TestAny_AlwaysTrue(t *testing.T) {
 
 	const typeName = "any"
 
-	checker := builtin.NewAny().Checker(typeName)
-	if checker == nil {
+	validator := builtin.AnyDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -76,7 +63,7 @@ func TestAny_AlwaysTrue(t *testing.T) {
 
 	for i, value := range values {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if !checker(value) {
+			if _, isValid := validator(value); !isValid {
 				t.Errorf("expect value to be valid")
 				t.Fail()
 			}
diff --git a/config/datatype/builtin/bool.go b/config/datatype/builtin/bool.go
new file mode 100644
index 0000000..a57721d
--- /dev/null
+++ b/config/datatype/builtin/bool.go
@@ -0,0 +1,31 @@
+package builtin
+
+import "git.xdrm.io/go/aicra/config/datatype"
+
+// BoolDataType is what its name tells
+type BoolDataType struct{}
+
+// Build returns the validator
+func (BoolDataType) Build(typeName string) datatype.Validator {
+	// nothing if type not handled
+	if typeName != "bool" {
+		return nil
+	}
+
+	return func(value interface{}) (interface{}, bool) {
+		switch cast := value.(type) {
+		case bool:
+			return cast, true
+
+		case string:
+			strVal := string(cast)
+			return strVal == "true", strVal == "true" || strVal == "false"
+		case []byte:
+			strVal := string(cast)
+			return strVal == "true", strVal == "true" || strVal == "false"
+
+		default:
+			return false, false
+		}
+	}
+}
diff --git a/typecheck/builtin/bool_test.go b/config/datatype/builtin/bool_test.go
similarity index 75%
rename from typecheck/builtin/bool_test.go
rename to config/datatype/builtin/bool_test.go
index 8e63344..52ef4c2 100644
--- a/typecheck/builtin/bool_test.go
+++ b/config/datatype/builtin/bool_test.go
@@ -4,26 +4,13 @@ import (
 	"fmt"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestBool_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewBool())
-
-	switch cast := inst.(type) {
-	case *builtin.Bool:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.Bool{}, cast)
-	}
-}
-
 func TestBool_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewBool()
+	dt := builtin.BoolDataType{}
 
 	tests := []struct {
 		Type    string
@@ -39,8 +26,8 @@ func TestBool_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			checker := inst.Checker(test.Type)
-			if checker == nil {
+			validator := dt.Build(test.Type)
+			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
 					t.Fail()
@@ -62,8 +49,8 @@ func TestBool_Values(t *testing.T) {
 
 	const typeName = "bool"
 
-	checker := builtin.NewBool().Checker(typeName)
-	if checker == nil {
+	validator := builtin.BoolDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -98,7 +85,7 @@ func TestBool_Values(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
diff --git a/config/datatype/builtin/float.go b/config/datatype/builtin/float.go
new file mode 100644
index 0000000..1e2fd18
--- /dev/null
+++ b/config/datatype/builtin/float.go
@@ -0,0 +1,47 @@
+package builtin
+
+import (
+	"encoding/json"
+
+	"git.xdrm.io/go/aicra/config/datatype"
+)
+
+// FloatDataType is what its name tells
+type FloatDataType struct{}
+
+// Build returns the validator
+func (FloatDataType) Build(typeName string) datatype.Validator {
+	// nothing if type not handled
+	if typeName != "float64" && typeName != "float" {
+		return nil
+	}
+	return func(value interface{}) (interface{}, bool) {
+		switch cast := value.(type) {
+
+		case int:
+			return float64(cast), true
+
+		case uint:
+			return float64(cast), true
+
+		case float64:
+			return cast, true
+
+			// serialized string -> try to convert to float
+		case []byte:
+			num := json.Number(cast)
+			floatVal, err := num.Float64()
+			return floatVal, err == nil
+
+		case string:
+			num := json.Number(cast)
+			floatVal, err := num.Float64()
+			return floatVal, err == nil
+
+			// unknown type
+		default:
+			return 0, false
+
+		}
+	}
+}
diff --git a/typecheck/builtin/float64_test.go b/config/datatype/builtin/float_test.go
similarity index 80%
rename from typecheck/builtin/float64_test.go
rename to config/datatype/builtin/float_test.go
index f1c10fc..f862521 100644
--- a/typecheck/builtin/float64_test.go
+++ b/config/datatype/builtin/float_test.go
@@ -5,26 +5,13 @@ import (
 	"math"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestFloat64_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewFloat64())
-
-	switch cast := inst.(type) {
-	case *builtin.Float64:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.Float64{}, cast)
-	}
-}
-
 func TestFloat64_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewFloat64()
+	dt := builtin.FloatDataType{}
 
 	tests := []struct {
 		Type    string
@@ -46,8 +33,8 @@ func TestFloat64_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			checker := inst.Checker(test.Type)
-			if checker == nil {
+			validator := dt.Build(test.Type)
+			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
 					t.Fail()
@@ -69,8 +56,8 @@ func TestFloat64_Values(t *testing.T) {
 
 	const typeName = "float"
 
-	checker := builtin.NewFloat64().Checker(typeName)
-	if checker == nil {
+	validator := builtin.FloatDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -110,7 +97,7 @@ func TestFloat64_Values(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
diff --git a/config/datatype/builtin/int.go b/config/datatype/builtin/int.go
new file mode 100644
index 0000000..a82e2ad
--- /dev/null
+++ b/config/datatype/builtin/int.go
@@ -0,0 +1,52 @@
+package builtin
+
+import (
+	"encoding/json"
+	"math"
+
+	"git.xdrm.io/go/aicra/config/datatype"
+)
+
+// IntDataType is what its name tells
+type IntDataType struct{}
+
+// Build returns the validator
+func (IntDataType) Build(typeName string) datatype.Validator {
+	// nothing if type not handled
+	if typeName != "int" {
+		return nil
+	}
+
+	return func(value interface{}) (interface{}, bool) {
+		switch cast := value.(type) {
+
+		case int:
+			return cast, true
+
+		case uint:
+			overflows := cast > math.MaxInt64
+			return int(cast), !overflows
+
+		case float64:
+			intVal := int(cast)
+			overflows := cast < float64(math.MinInt64) || cast > float64(math.MaxInt64)
+			return intVal, cast == float64(intVal) && !overflows
+
+			// serialized string -> try to convert to float
+		case string:
+			num := json.Number(cast)
+			intVal, err := num.Int64()
+			return int(intVal), err == nil
+			// serialized string -> try to convert to float
+
+		case []byte:
+			num := json.Number(cast)
+			intVal, err := num.Int64()
+			return int(intVal), err == nil
+
+			// unknown type
+		default:
+			return 0, false
+		}
+	}
+}
diff --git a/typecheck/builtin/int_test.go b/config/datatype/builtin/int_test.go
similarity index 81%
rename from typecheck/builtin/int_test.go
rename to config/datatype/builtin/int_test.go
index 0461847..c3126f3 100644
--- a/typecheck/builtin/int_test.go
+++ b/config/datatype/builtin/int_test.go
@@ -5,26 +5,13 @@ import (
 	"math"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestInt_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewInt())
-
-	switch cast := inst.(type) {
-	case *builtin.Int:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.Int{}, cast)
-	}
-}
-
 func TestInt_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewInt()
+	dt := builtin.IntDataType{}
 
 	tests := []struct {
 		Type    string
@@ -40,8 +27,8 @@ func TestInt_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			checker := inst.Checker(test.Type)
-			if checker == nil {
+			validator := dt.Build(test.Type)
+			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
 					t.Fail()
@@ -63,8 +50,8 @@ func TestInt_Values(t *testing.T) {
 
 	const typeName = "int"
 
-	checker := builtin.NewInt().Checker(typeName)
-	if checker == nil {
+	validator := builtin.IntDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -110,7 +97,7 @@ func TestInt_Values(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
diff --git a/typecheck/builtin/string.go b/config/datatype/builtin/string.go
similarity index 72%
rename from typecheck/builtin/string.go
rename to config/datatype/builtin/string.go
index 02501a1..95d1fff 100644
--- a/typecheck/builtin/string.go
+++ b/config/datatype/builtin/string.go
@@ -4,28 +4,24 @@ import (
 	"regexp"
 	"strconv"
 
-	"git.xdrm.io/go/aicra/typecheck"
+	"git.xdrm.io/go/aicra/config/datatype"
 )
 
 var fixedLengthRegex = regexp.MustCompile(`^string\((\d+)\)$`)
 var variableLengthRegex = regexp.MustCompile(`^string\((\d+), ?(\d+)\)$`)
 
-// String checks if a value is a string
-type String struct{}
+// StringDataType is what its name tells
+type StringDataType struct{}
 
-// NewString returns a bare string type checker
-func NewString() *String {
-	return &String{}
-}
-
-// Checker returns the checker function. Availables type names are : `string`, `string(length)` and `string(minLength, maxLength)`.
-func (s String) Checker(typeName string) typecheck.CheckerFunc {
-	isSimpleString := typeName == "string"
+// Build returns the validator.
+// availables type names are : `string`, `string(length)` and `string(minLength, maxLength)`.
+func (s StringDataType) Build(typeName string) datatype.Validator {
+	simple := typeName == "string"
 	fixedLengthMatches := fixedLengthRegex.FindStringSubmatch(typeName)
 	variableLengthMatches := variableLengthRegex.FindStringSubmatch(typeName)
 
 	// nothing if type not handled
-	if !isSimpleString && fixedLengthMatches == nil && variableLengthMatches == nil {
+	if !simple && fixedLengthMatches == nil && variableLengthMatches == nil {
 		return nil
 	}
 
@@ -53,10 +49,10 @@ func (s String) Checker(typeName string) typecheck.CheckerFunc {
 		max = exMax
 	}
 
-	return func(value interface{}) bool {
+	return func(value interface{}) (interface{}, bool) {
 		// preprocessing error
 		if mustFail {
-			return false
+			return "", false
 		}
 
 		// check type
@@ -68,21 +64,21 @@ func (s String) Checker(typeName string) typecheck.CheckerFunc {
 		}
 
 		if !isString {
-			return false
+			return "", false
 		}
 
-		if isSimpleString {
-			return true
+		if simple {
+			return strValue, true
 		}
 
 		// check length against previously extracted length
 		l := len(strValue)
-		return l >= min && l <= max
+		return strValue, l >= min && l <= max
 	}
 }
 
 // getFixedLength returns the fixed length from regex matches and a success state.
-func (String) getFixedLength(regexMatches []string) (int, bool) {
+func (StringDataType) getFixedLength(regexMatches []string) (int, bool) {
 	// incoherence error
 	if regexMatches == nil || len(regexMatches) < 2 {
 		return 0, false
@@ -98,7 +94,7 @@ func (String) getFixedLength(regexMatches []string) (int, bool) {
 }
 
 // getVariableLength returns the length min and max from regex matches and a success state.
-func (String) getVariableLength(regexMatches []string) (int, int, bool) {
+func (StringDataType) getVariableLength(regexMatches []string) (int, int, bool) {
 	// incoherence error
 	if regexMatches == nil || len(regexMatches) < 3 {
 		return 0, 0, false
diff --git a/typecheck/builtin/string_test.go b/config/datatype/builtin/string_test.go
similarity index 85%
rename from typecheck/builtin/string_test.go
rename to config/datatype/builtin/string_test.go
index d23b7bf..e332ea3 100644
--- a/typecheck/builtin/string_test.go
+++ b/config/datatype/builtin/string_test.go
@@ -4,26 +4,13 @@ import (
 	"fmt"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestString_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewString())
-
-	switch cast := inst.(type) {
-	case *builtin.String:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.String{}, cast)
-	}
-}
-
 func TestString_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewString()
+	dt := builtin.StringDataType{}
 
 	tests := []struct {
 		Type    string
@@ -66,9 +53,9 @@ func TestString_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			checker := inst.Checker(test.Type)
+			validator := dt.Build(test.Type)
 
-			if checker == nil {
+			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
 				}
@@ -88,8 +75,8 @@ func TestString_AnyLength(t *testing.T) {
 
 	const typeName = "string"
 
-	checker := builtin.NewString().Checker(typeName)
-	if checker == nil {
+	validator := builtin.StringDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -107,7 +94,7 @@ func TestString_AnyLength(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
@@ -146,14 +133,14 @@ func TestString_FixedLength(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			checker := builtin.NewString().Checker(test.Type)
-			if checker == nil {
+			validator := builtin.StringDataType{}.Build(test.Type)
+			if validator == nil {
 				t.Errorf("expect %q to be handled", test.Type)
 				t.Fail()
 				return
 			}
 
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
@@ -207,14 +194,14 @@ func TestString_VariableLength(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			checker := builtin.NewString().Checker(test.Type)
-			if checker == nil {
+			validator := builtin.StringDataType{}.Build(test.Type)
+			if validator == nil {
 				t.Errorf("expect %q to be handled", test.Type)
 				t.Fail()
 				return
 			}
 
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
diff --git a/config/datatype/builtin/uint.go b/config/datatype/builtin/uint.go
new file mode 100644
index 0000000..ab02728
--- /dev/null
+++ b/config/datatype/builtin/uint.go
@@ -0,0 +1,58 @@
+package builtin
+
+import (
+	"encoding/json"
+	"math"
+
+	"git.xdrm.io/go/aicra/config/datatype"
+)
+
+// UintDataType is what its name tells
+type UintDataType struct{}
+
+// Build returns the validator
+func (UintDataType) Build(typeName string) datatype.Validator {
+	// nothing if type not handled
+	if typeName != "uint" {
+		return nil
+	}
+
+	return func(value interface{}) (interface{}, bool) {
+		switch cast := value.(type) {
+
+		case int:
+			return uint(cast), cast >= 0
+
+		case uint:
+			return cast, true
+
+		case float64:
+			uintVal := uint(cast)
+			overflows := cast < 0 || cast > math.MaxUint64
+			return uintVal, cast == float64(uintVal) && !overflows
+
+			// serialized string -> try to convert to float
+		case string:
+			num := json.Number(cast)
+			floatVal, err := num.Float64()
+			if err != nil {
+				return 0, false
+			}
+			overflows := floatVal < 0 || floatVal > math.MaxUint64
+			return uint(floatVal), !overflows
+
+		case []byte:
+			num := json.Number(cast)
+			floatVal, err := num.Float64()
+			if err != nil {
+				return 0, false
+			}
+			overflows := floatVal < 0 || floatVal > math.MaxUint64
+			return uint(floatVal), !overflows
+
+			// unknown type
+		default:
+			return 0, false
+		}
+	}
+}
diff --git a/typecheck/builtin/uint_test.go b/config/datatype/builtin/uint_test.go
similarity index 82%
rename from typecheck/builtin/uint_test.go
rename to config/datatype/builtin/uint_test.go
index 4a6ceb8..ae4ef03 100644
--- a/typecheck/builtin/uint_test.go
+++ b/config/datatype/builtin/uint_test.go
@@ -5,26 +5,13 @@ import (
 	"math"
 	"testing"
 
-	"git.xdrm.io/go/aicra/typecheck/builtin"
+	"git.xdrm.io/go/aicra/config/datatype/builtin"
 )
 
-func TestUint_New(t *testing.T) {
-	t.Parallel()
-
-	inst := interface{}(builtin.NewUint())
-
-	switch cast := inst.(type) {
-	case *builtin.Uint:
-		return
-	default:
-		t.Errorf("expect %T ; got %T", &builtin.Uint{}, cast)
-	}
-}
-
 func TestUint_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	inst := builtin.NewUint()
+	dt := builtin.UintDataType{}
 
 	tests := []struct {
 		Type    string
@@ -40,8 +27,8 @@ func TestUint_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			checker := inst.Checker(test.Type)
-			if checker == nil {
+			validator := dt.Build(test.Type)
+			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
 					t.Fail()
@@ -63,8 +50,8 @@ func TestUint_Values(t *testing.T) {
 
 	const typeName = "uint"
 
-	checker := builtin.NewUint().Checker(typeName)
-	if checker == nil {
+	validator := builtin.UintDataType{}.Build(typeName)
+	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
 	}
@@ -110,7 +97,7 @@ func TestUint_Values(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			if checker(test.Value) {
+			if _, isValid := validator(test.Value); isValid {
 				if !test.Valid {
 					t.Errorf("expect value to be invalid")
 					t.Fail()
diff --git a/typecheck/builtin/any.go b/typecheck/builtin/any.go
deleted file mode 100644
index 9be7254..0000000
--- a/typecheck/builtin/any.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package builtin
-
-import "git.xdrm.io/go/aicra/typecheck"
-
-// Any is a permissive type checker
-type Any struct{}
-
-// NewAny returns a bare any type checker
-func NewAny() *Any {
-	return &Any{}
-}
-
-// Checker returns the checker function
-func (Any) Checker(typeName string) typecheck.CheckerFunc {
-	// nothing if type not handled
-	if typeName != "any" {
-		return nil
-	}
-	return func(interface{}) bool {
-		return true
-	}
-}
diff --git a/typecheck/builtin/bool.go b/typecheck/builtin/bool.go
deleted file mode 100644
index 2d5ae07..0000000
--- a/typecheck/builtin/bool.go
+++ /dev/null
@@ -1,44 +0,0 @@
-package builtin
-
-import "git.xdrm.io/go/aicra/typecheck"
-
-// Bool checks if a value is a boolean
-type Bool struct{}
-
-// NewBool returns a bare boolean type checker
-func NewBool() *Bool {
-	return &Bool{}
-}
-
-// Checker returns the checker function
-func (Bool) Checker(typeName string) typecheck.CheckerFunc {
-	// nothing if type not handled
-	if typeName != "bool" {
-		return nil
-	}
-	return func(value interface{}) bool {
-		_, isBool := readBool(value)
-		return isBool
-	}
-}
-
-// readBool tries to read a serialized boolean and returns whether it succeeded.
-func readBool(value interface{}) (bool, bool) {
-	switch cast := value.(type) {
-	case bool:
-		return cast, true
-
-	case string:
-		strVal := string(cast)
-		return strVal == "true", strVal == "true" || strVal == "false"
-
-	case []byte:
-		strVal := string(cast)
-		return strVal == "true", strVal == "true" || strVal == "false"
-
-	default:
-		return false, false
-	}
-
-	return false, false
-}
diff --git a/typecheck/builtin/float64.go b/typecheck/builtin/float64.go
deleted file mode 100644
index 081ac06..0000000
--- a/typecheck/builtin/float64.go
+++ /dev/null
@@ -1,58 +0,0 @@
-package builtin
-
-import (
-	"encoding/json"
-
-	"git.xdrm.io/go/aicra/typecheck"
-)
-
-// Float64 checks if a value is a float64
-type Float64 struct{}
-
-// NewFloat64 returns a bare number type checker
-func NewFloat64() *Float64 {
-	return &Float64{}
-}
-
-// Checker returns the checker function
-func (Float64) Checker(typeName string) typecheck.CheckerFunc {
-	// nothing if type not handled
-	if typeName != "float64" && typeName != "float" {
-		return nil
-	}
-	return func(value interface{}) bool {
-		_, isFloat := readFloat(value)
-		return isFloat
-	}
-}
-
-// readFloat tries to read a serialized float and returns whether it succeeded.
-func readFloat(value interface{}) (float64, bool) {
-	switch cast := value.(type) {
-
-	case int:
-		return float64(cast), true
-
-	case uint:
-		return float64(cast), true
-
-	case float64:
-		return cast, true
-
-		// serialized string -> try to convert to float
-	case string:
-		num := json.Number(cast)
-		floatVal, err := num.Float64()
-		return floatVal, err == nil
-
-	case []byte:
-		num := json.Number(cast)
-		floatVal, err := num.Float64()
-		return floatVal, err == nil
-
-		// unknown type
-	default:
-		return 0, false
-
-	}
-}
diff --git a/typecheck/builtin/int.go b/typecheck/builtin/int.go
deleted file mode 100644
index a64c0df..0000000
--- a/typecheck/builtin/int.go
+++ /dev/null
@@ -1,64 +0,0 @@
-package builtin
-
-import (
-	"encoding/json"
-	"math"
-
-	"git.xdrm.io/go/aicra/typecheck"
-)
-
-// Int checks if a value is an int
-type Int struct{}
-
-// NewInt returns a bare number type checker
-func NewInt() *Int {
-	return &Int{}
-}
-
-// Checker returns the checker function
-func (Int) Checker(typeName string) typecheck.CheckerFunc {
-	// nothing if type not handled
-	if typeName != "int" {
-		return nil
-	}
-	return func(value interface{}) bool {
-		_, isInt := readInt(value)
-
-		return isInt
-	}
-}
-
-// readInt tries to read a serialized int and returns whether it succeeded.
-func readInt(value interface{}) (int, bool) {
-	switch cast := value.(type) {
-
-	case int:
-		return cast, true
-
-	case uint:
-		overflows := cast > math.MaxInt64
-		return int(cast), !overflows
-
-	case float64:
-		intVal := int(cast)
-		overflows := cast < float64(math.MinInt64) || cast > float64(math.MaxInt64)
-		return intVal, cast == float64(intVal) && !overflows
-
-		// serialized string -> try to convert to float
-	case string:
-		num := json.Number(cast)
-		intVal, err := num.Int64()
-		return int(intVal), err == nil
-		// serialized string -> try to convert to float
-
-	case []byte:
-		num := json.Number(cast)
-		intVal, err := num.Int64()
-		return int(intVal), err == nil
-
-		// unknown type
-	default:
-		return 0, false
-
-	}
-}
diff --git a/typecheck/builtin/uint.go b/typecheck/builtin/uint.go
deleted file mode 100644
index 7feb9a4..0000000
--- a/typecheck/builtin/uint.go
+++ /dev/null
@@ -1,70 +0,0 @@
-package builtin
-
-import (
-	"encoding/json"
-	"math"
-
-	"git.xdrm.io/go/aicra/typecheck"
-)
-
-// Uint checks if a value is an uint
-type Uint struct{}
-
-// NewUint returns a bare number type checker
-func NewUint() *Uint {
-	return &Uint{}
-}
-
-// Checker returns the checker function
-func (Uint) Checker(typeName string) typecheck.CheckerFunc {
-	// nothing if type not handled
-	if typeName != "uint" {
-		return nil
-	}
-	return func(value interface{}) bool {
-		_, isInt := readUint(value)
-
-		return isInt
-	}
-}
-
-// readUint tries to read a serialized uint and returns whether it succeeded.
-func readUint(value interface{}) (uint, bool) {
-	switch cast := value.(type) {
-
-	case int:
-		return uint(cast), cast >= 0
-
-	case uint:
-		return cast, true
-
-	case float64:
-		uintVal := uint(cast)
-		overflows := cast < 0 || cast > math.MaxUint64
-		return uintVal, cast == float64(uintVal) && !overflows
-
-		// serialized string -> try to convert to float
-	case string:
-		num := json.Number(cast)
-		floatVal, err := num.Float64()
-		if err != nil {
-			return 0, false
-		}
-		overflows := floatVal < 0 || floatVal > math.MaxUint64
-		return uint(floatVal), !overflows
-
-	case []byte:
-		num := json.Number(cast)
-		floatVal, err := num.Float64()
-		if err != nil {
-			return 0, false
-		}
-		overflows := floatVal < 0 || floatVal > math.MaxUint64
-		return uint(floatVal), !overflows
-
-		// unknown type
-	default:
-		return 0, false
-
-	}
-}