Signature help

fixtures/signature/funcClosed.php

@@ -0,0 +1,7 @@
+<?php
+
+function helpFunc1(int $count = 0)
+{
+}
+
+helpFunc1()

fixtures/signature/funcNotClosed.php

@@ -0,0 +1,7 @@
+<?php
+
+function helpFunc2(int $count = 0)
+{
+}
+
+helpFunc2(

fixtures/signature/methodActiveParam.php

@@ -0,0 +1,15 @@
+<?php
+
+class HelpClass5
+{
+    public function method(string $param = "", int $count = 0, bool $test = null)
+    {
+    }
+    public function test()
+    {
+        $this->method();
+    }
+}
+
+$a = new HelpClass5;
+$a->method("asdf", 123, true);

fixtures/signature/methodClosed.php

@@ -0,0 +1,15 @@
+<?php
+
+class HelpClass1
+{
+    public function method(string $param = "")
+    {
+    }
+    public function test()
+    {
+        $this->method();
+    }
+}
+
+$a = new HelpClass1;
+$a->method();

fixtures/signature/methodNotClosed.php

@@ -0,0 +1,17 @@
+<?php
+
+class HelpClass2
+{
+    protected function method(string $param = "")
+    {
+    }
+    public function test()
+    {
+        $this->method(1,1);
+    }
+}
+$a = new HelpClass2;
+$a
+    ->method(
+        1,
+        array(),

fixtures/signature/staticClosed.php

@@ -0,0 +1,10 @@
+<?php
+
+class HelpClass3
+{
+    public static function method(string $param = "")
+    {
+    }
+}
+
+HelpClass3::method()

fixtures/signature/staticNotClosed.php

@@ -0,0 +1,10 @@
+<?php
+
+class HelpClass4
+{
+    public static function method(string $param = "")
+    {
+    }
+}
+
+HelpClass4::method(1

src/Definition.php

@@ -6,6 +6,7 @@
 use LanguageServer\Index\ReadableIndex;
 use phpDocumentor\Reflection\{Types, Type, Fqsen, TypeResolver};
 use LanguageServer\Protocol\SymbolInformation;
+use LanguageServer\Protocol\ParameterInformation;
 use Exception;
 use Generator;
 
@@ -98,6 +99,13 @@ class Definition
      * @var string
      */
     public $documentation;
+
+    /**
+     * Parameters array (for methods and functions), for use in textDocument/signatureHelp
+     *
+     * @var ParameterInformation[]
+     */
+    public $parameters;
 
     /**
      * Yields the definitons of all ancestor classes (the Definition fqn is yielded as key)

src/DefinitionResolver.php

@@ -5,8 +5,12 @@
 
 use LanguageServer\Index\ReadableIndex;
 use LanguageServer\Protocol\SymbolInformation;
+use LanguageServer\Protocol\ParameterInformation;
 use Microsoft\PhpParser;
 use Microsoft\PhpParser\Node;
+use Microsoft\PhpParser\Node\Expression\AnonymousFunctionCreationExpression;
+use Microsoft\PhpParser\Node\MethodDeclaration;
+use Microsoft\PhpParser\Node\Statement\FunctionDeclaration;
 use phpDocumentor\Reflection\{
     DocBlock, DocBlockFactory, Fqsen, Type, TypeResolver, Types
 };
@@ -232,6 +236,20 @@ public function createDefinitionFromNode(Node $node, string $fqn = null): Defini
             $def->documentation = $this->getDocumentationFromNode($node);
         }
 
+        $def->parameters = [];
+        if (($node instanceof MethodDeclaration ||
+             $node instanceof FunctionDeclaration ||
+             $node instanceof AnonymousFunctionCreationExpression) &&
+            $node->parameters !== null
+        ) {
+            foreach ($node->parameters->getElements() as $param) {
+                $def->parameters[] = new ParameterInformation(
+                    $this->getDeclarationLineFromNode($param),
+                    $this->getDocumentationFromNode($param)
+                );
+            }
+        }
+
         return $def;
     }
 

src/LanguageServer.php

@@ -9,7 +9,8 @@
     TextDocumentSyncKind,
     Message,
     InitializeResult,
-    CompletionOptions
+    CompletionOptions,
+    SignatureHelpOptions
 };
 use LanguageServer\FilesFinder\{FilesFinder, ClientFilesFinder, FileSystemFilesFinder};
 use LanguageServer\ContentRetriever\{ContentRetriever, ClientContentRetriever, FileSystemContentRetriever};
@@ -275,6 +276,9 @@ public function initialize(ClientCapabilities $capabilities, string $rootPath =
             $serverCapabilities->completionProvider = new CompletionOptions;
             $serverCapabilities->completionProvider->resolveProvider = false;
             $serverCapabilities->completionProvider->triggerCharacters = ['$', '>'];
+            // support signature help
+            $serverCapabilities->signatureHelpProvider = new SignatureHelpOptions;
+            $serverCapabilities->signatureHelpProvider->triggerCharacters = ['(',','];
             // Support global references
             $serverCapabilities->xworkspaceReferencesProvider = true;
             $serverCapabilities->xdefinitionProvider = true;

src/Protocol/ParameterInformation.php

@@ -23,4 +23,13 @@ class ParameterInformation
      * @var string|null
      */
     public $documentation;
+    /**
+     * @param string                 $label         The label of this signature. Will be shown in the UI.
+     * @param string|null            $documentation The human-readable doc-comment of this signature.
+     */
+    public function __construct(string $label = null, string $documentation = null)
+    {
+        $this->label = $label;
+        $this->documentation = $documentation;
+    }
 }

src/Protocol/SignatureHelp.php

@@ -29,4 +29,15 @@ class SignatureHelp
      * @var int|null
      */
     public $activeParameter;
+    /**
+     * @param SignatureInformation[] $signatures      The signatures.
+     * @param int|null               $activeSignature The active signature.
+     * @param int|null               $activeParameter The active parameter of the active signature.
+     */
+    public function __construct(array $signatures = [], int $activeSignature = null, int $activeParameter = null)
+    {
+        $this->signatures = $signatures;
+        $this->activeSignature = $activeSignature;
+        $this->activeParameter = $activeParameter;
+    }
 }

src/Protocol/SignatureInformation.php

@@ -31,4 +31,16 @@ class SignatureInformation
      * @var ParameterInformation[]|null
      */
     public $parameters;
+
+    /**
+     * @param string                      $label         The label of this signature. Will be shown in the UI.
+     * @param string|null                 $documentation The human-readable doc-comment of this signature.
+     * @param ParameterInformation[]|null $parameters    The parameters of this signature.
+     */
+    public function __construct(string $label = null, string $documentation = null, array $parameters = null)
+    {
+        $this->label = $label;
+        $this->documentation = $documentation;
+        $this->parameters = $parameters;
+    }
 }

src/Server/TextDocument.php

@@ -4,7 +4,7 @@
 namespace LanguageServer\Server;
 
 use LanguageServer\{
-    CompletionProvider, LanguageClient, PhpDocument, PhpDocumentLoader, DefinitionResolver
+    CompletionProvider, LanguageClient, PhpDocument, PhpDocumentLoader, DefinitionResolver, SignatureHelpProvider
 };
 use LanguageServer\Index\ReadableIndex;
 use LanguageServer\Protocol\{
@@ -73,6 +73,10 @@ class TextDocument
      * @var \stdClass|null
      */
     protected $composerLock;
+    /**
+     * @var SignatureHelpProvider
+     */
+    protected $signatureHelpProvider;
 
     /**
      * @param PhpDocumentLoader $documentLoader
@@ -94,6 +98,7 @@ public function __construct(
         $this->client = $client;
         $this->definitionResolver = $definitionResolver;
         $this->completionProvider = new CompletionProvider($this->definitionResolver, $index);
+        $this->signatureHelpProvider = new SignatureHelpProvider($this->definitionResolver, $index);
         $this->index = $index;
         $this->composerJson = $composerJson;
         $this->composerLock = $composerLock;
@@ -399,4 +404,20 @@ public function xdefinition(TextDocumentIdentifier $textDocument, Position $posi
             return [new SymbolLocationInformation($descriptor, $def->symbolInformation->location)];
         });
     }
+
+    /**
+     * The signature help request is sent from the client to the server to request signature information
+     * at a given cursor position.
+     *
+     * @param TextDocumentIdentifier $textDocument The text document
+     * @param Position               $position     The position inside the text document
+     * @return Promise <SignatureHelp>
+     */
+    public function signatureHelp(TextDocumentIdentifier $textDocument, Position $position): Promise
+    {
+        return coroutine(function () use ($textDocument, $position) {
+            $document = yield $this->documentLoader->getOrLoad($textDocument->uri);
+            return $this->signatureHelpProvider->provideSignature($document, $position);
+        });
+    }
 }

src/SignatureHelpProvider.php

@@ -0,0 +1,111 @@
+<?php
+declare(strict_types = 1);
+
+namespace LanguageServer;
+
+use Microsoft\PhpParser\Node\DelimitedList\ArgumentExpressionList;
+use Microsoft\PhpParser\Node\Expression\CallExpression;
+use Microsoft\PhpParser\Node\Expression\ArgumentExpression;
+use LanguageServer\Index\ReadableIndex;
+use LanguageServer\Protocol\{
+    Range,
+    Position,
+    SignatureHelp,
+    SignatureInformation,
+    ParameterInformation
+};
+
+class SignatureHelpProvider
+{
+    /**
+     * @var DefinitionResolver
+     */
+    private $definitionResolver;
+
+    /**
+     * @var ReadableIndex
+     */
+    private $index;
+
+    /**
+     * @param DefinitionResolver $definitionResolver
+     * @param ReadableIndex      $index
+     */
+    public function __construct(DefinitionResolver $definitionResolver, ReadableIndex $index)
+    {
+        $this->definitionResolver = $definitionResolver;
+        $this->index = $index;
+    }
+
+    /**
+     * Get the short declaration for a callable (class modifiers, function keyword, etc are stripped)
+     *
+     * @param string $declaration
+     * @return string
+     */
+    protected function getShortDeclaration(string $declaration): string
+    {
+        $parts = explode('(', $declaration, 2);
+        $name = array_reverse(explode(' ', trim($parts[0])))[0];
+        return $name . '(' . $parts[1];
+    }
+
+    /**
+     * Returns signature help for a specific cursor position in a document
+     *
+     * @param PhpDocument $doc The opened document
+     * @param Position $pos The cursor position
+     * @return SignatureHelp
+     */
+    public function provideSignature(PhpDocument $doc, Position $pos) : SignatureHelp
+    {
+        $node = $doc->getNodeAtPosition($pos);
+        $arge = null;
+        while ($node &&
+            !($node instanceof ArgumentExpressionList) &&
+            !($node instanceof CallExpression) &&
+            $node->parent
+        ) {
+            if ($node instanceof ArgumentExpression) {
+                $arge = $node;
+            }
+            $node = $node->parent;
+        }
+        if (!($node instanceof ArgumentExpressionList) &&
+            !($node instanceof CallExpression)
+        ) {
+            return new SignatureHelp;
+        }
+        $count = null;
+        if ($node instanceof ArgumentExpressionList) {
+            $count = 0;
+            foreach ($node->getElements() as $param) {
+                if ($param === $arge) {
+                    break;
+                }
+                $count ++;
+            }
+            while ($node && !($node instanceof CallExpression) && $node->parent) {
+                $node = $node->parent;
+            }
+            if (!($node instanceof CallExpression)) {
+                return new SignatureHelp;
+            }
+        }
+        $def = $this->definitionResolver->resolveReferenceNodeToDefinition($node->callableExpression);
+        if (!$def) {
+            return new SignatureHelp;
+        }
+        return new SignatureHelp(
+            [
+                new SignatureInformation(
+                    $this->getShortDeclaration($def->declarationLine),
+                    $def->documentation,
+                    $def->parameters
+                )
+            ],
+            0,
+            $count !== null && $def->parameters !== null && $count < count($def->parameters) ? $count : null
+        );
+    }
+}

tests/LanguageServerTest.php

@@ -14,7 +14,8 @@
     TextDocumentIdentifier,
     InitializeResult,
     ServerCapabilities,
-    CompletionOptions
+    CompletionOptions,
+    SignatureHelpOptions
 };
 use AdvancedJsonRpc;
 use Webmozart\Glob\Glob;
@@ -40,6 +41,8 @@ public function testInitialize()
         $serverCapabilities->completionProvider = new CompletionOptions;
         $serverCapabilities->completionProvider->resolveProvider = false;
         $serverCapabilities->completionProvider->triggerCharacters = ['$', '>'];
+        $serverCapabilities->signatureHelpProvider = new SignatureHelpOptions;
+        $serverCapabilities->signatureHelpProvider->triggerCharacters = ['(',','];
         $serverCapabilities->xworkspaceReferencesProvider = true;
         $serverCapabilities->xdefinitionProvider = true;
         $serverCapabilities->xdependenciesProvider = true;