WIP: PoC expose a fluent api to generate code

.github/workflows/ci.yml

@@ -26,10 +26,11 @@ jobs:
         uses: actions/setup-go@v4
         with:
           go-version: ${{ matrix.go }}
-      - run: make deps
-      - run: make lint
-      - run: make install
-      - run: make test
-      - run: make build
-      - run: make test-examples
-        if: matrix.os != 'windows-latest'
+      - name: Download dependencies
+        run: go mod download
+      - name: Install golangci-lint
+        run: go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
+      - name: Run golangci-lint
+        run: golangci-lint run
+      - name: Run tests
+        run: go test -v ./...

examples/1_validator/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"bytes"
+	genz2 "github.com/Joffref/genz/genz"
+	"github.com/Joffref/genz/genz/cli"
+	"github.com/Joffref/genz/genz/models"
+	"io"
+)
+
+func main() {
+	err := cli.NewCommandFromGenerator("validator", MyCustomGenerator).Execute()
+	if err != nil {
+		return
+	}
+}
+
+func MyCustomGenerator(file io.Writer, element models.ParsedElement) error {
+	code := genz2.NewCode(file, element.PackageName).
+		WithHeaderComments("File generated by GenZ with template validator").
+		WithImports("fmt", "unicode").
+		WithDeclarations(
+			genz2.Function("Validate").
+				WithReceiver("v", element.Type.InternalName, false).
+				WithReturns("error").
+				WithBody(body(element.Element)),
+		)
+	err := code.Generate()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func body(element models.Element) string {
+	var buf bytes.Buffer
+	for _, attribute := range element.Attributes {
+		if attribute.Type.InternalName == "string" {
+			for _, comment := range attribute.Comments {
+				if comment == "+required" {
+					buf.WriteString("if v." + attribute.Name + " == \"\" {\n")
+					buf.WriteString("return fmt.Errorf(\"attribute '" + attribute.Name + "' must be set\")\n")
+					buf.WriteString("}\n")
+				}
+				if comment == "+startsWithCapital" {
+					buf.WriteString("if v." + attribute.Name + " != \"\" && !unicode.IsUpper(rune(v." + attribute.Name + "[0])) {\n")
+					buf.WriteString("return fmt.Errorf(\"attribute '" + attribute.Name + "' should start with a capital letter\")\n")
+					buf.WriteString("}\n")
+				}
+			}
+		}
+	}
+	buf.WriteString("return nil")
+	return buf.String()
+}