From 19d7cc469aa1d77393d36fecf9c2dcf0177025af Mon Sep 17 00:00:00 2001
From: mappu <mappu04@gmail.com>
Date: Tue, 7 Apr 2020 21:53:00 +1200
Subject: [PATCH] node: support interfaces

---
 README.md                    |  2 +-
 fixtures/0007-interfaces.php |  9 ++++++
 node.go                      | 58 ++++++++++++++++++++++++++++++++----
 3 files changed, 62 insertions(+), 7 deletions(-)
 create mode 100644 fixtures/0007-interfaces.php

diff --git a/README.md b/README.md
index b7b7efc..324a5f6 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ The goal is to produce idiomatic, maintainable Go code as part of a one-off conv
 		- *PHP variable names are case-sensitive, function names are case-insensitive*
 	- [X] Static methods
 	- [X] Inheritance *partial*
-	- [ ] Interfaces
+	- [X] Interfaces
 	- [X] super
 		- [X] Need to track current conversion state through into function generator, to select the concrete parent
 	- [X] parent::
diff --git a/fixtures/0007-interfaces.php b/fixtures/0007-interfaces.php
new file mode 100644
index 0000000..bd3c26d
--- /dev/null
+++ b/fixtures/0007-interfaces.php
@@ -0,0 +1,9 @@
+<?php
+
+interface Base {
+	function Foo();
+}
+
+class Child implements Base {
+	function Foo() {}
+}
diff --git a/node.go b/node.go
index dbc52ca..590daf7 100644
--- a/node.go
+++ b/node.go
@@ -105,7 +105,7 @@ func (this *conversionState) convertNoFreeFloating(n_ node.Node) (string, error)
 			}
 
 			switch s.(type) {
-			case *stmt.Class, *stmt.Function:
+			case *stmt.Class, *stmt.Function, *stmt.Interface:
 				// Declaration - emit immediately (hoist)
 				ret += sm + "\n"
 
@@ -265,12 +265,56 @@ func (this *conversionState) convertNoFreeFloating(n_ node.Node) (string, error)
 		// Create all member functions
 		ret += strings.Join(memberFuncs, "\n\n")
 
+		if n.Implements != nil {
+			for _, ifaceName_ := range n.Implements.InterfaceNames {
+				ifaceName, err := this.resolveName(ifaceName_)
+				if err != nil {
+					return "", parseErr{ifaceName_, err}
+				}
+
+				// Add extra interface assertion statement
+				ret += "var _ " + ifaceName + " = &" + className + "{} // interface assertion\n"
+
+			}
+		}
+
 		// Done
 		// Reinstate parent state before returning
 		this.currentClassName = prevClassName
 		this.currentClassParentName = prevClassParentName
 		return ret, nil
 
+	case *stmt.Interface:
+
+		ifaceName := n.InterfaceName.(*node.Identifier).Value
+
+		ret := "type " + ifaceName + " interface {\n"
+
+		for _, ss := range n.Stmts {
+			classMethod, ok := ss.(*stmt.ClassMethod)
+			if !ok {
+				return "", parseErr{ss, fmt.Errorf("expected stmt.ClassMethod")}
+			}
+
+			methodName, err := applyVisibilityModifier(classMethod.MethodName.(*node.Identifier).Value, classMethod.Modifiers)
+			if err != nil {
+				return "", parseErr{ss, err}
+			}
+
+			// TODO classMethod.PhpDocComment
+
+			arglist, err := this.convertFunctionCommon(classMethod.Params, classMethod.ReturnType, classMethod.ReturnsRef, nil)
+			if err != nil {
+				return "", parseErr{ss, err}
+			}
+
+			ret += methodName + arglist + "\n"
+		}
+
+		ret += "}\n"
+
+		return ret, nil
+
 	case *stmt.Function:
 		// Top-level function definition
 		// TODO parse doc comment
@@ -1154,12 +1198,14 @@ func (this *conversionState) convertFunctionCommon(params []node.Node, returnTyp
 
 	// Recurse through body statements
 
-	fullBody, err := this.convert(stmt.NewStmtList(bodyStmts))
-	if err != nil {
-		return "", err
-	}
+	if bodyStmts != nil {
+		fullBody, err := this.convert(stmt.NewStmtList(bodyStmts))
+		if err != nil {
+			return "", err
+		}
 
-	ret += fullBody + "\n"
+		ret += fullBody + "\n"
+	}
 
 	// Done
 	// No extra trailing newline in case this is part of a large expression