From 84d815f4e006e02521759070bb89025dab80b219 Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Sat, 24 May 2014 01:39:33 +0200
Subject: Added scoping.

ste:mktag generated tags now have an own scope. They even resemble
closures, since they inherit their parent scope.

A lot of work was done to keep this compatible with older programs.
However:

* Templates that relied on the non-scoping behavior of tags will probably
  fail.
* Since $ste->vars is no longer an actual array, things like
    $ste->vars["foo"]["bar"] = "baz"
  are no longer possible! A single field access will still work:
    $ste->vars["foo"] = "bar"
---
 STECore.php                     | 114 +++++++++++++++---------
 Scope.php                       | 187 ++++++++++++++++++++++++++++++++++++++++
 Transcompiler.php               |   6 +-
 VarNotInScope.php               |   5 ++
 ste.php                         |   3 +
 tests/test_closure/.gitignore   |   3 +
 tests/test_closure/code.php     |   5 ++
 tests/test_closure/test.tpl     |   8 ++
 tests/test_closure/want         |   1 +
 tests/test_mktag/test.tpl       |   3 +-
 tests/test_recursive/.gitignore |   3 +
 tests/test_recursive/code.php   |   5 ++
 tests/test_recursive/test.tpl   |  11 +++
 tests/test_recursive/want       |   1 +
 tests/test_scoping/.gitignore   |   3 +
 tests/test_scoping/code.php     |   5 ++
 tests/test_scoping/test.tpl     |   6 ++
 tests/test_scoping/want         |   0
 18 files changed, 321 insertions(+), 48 deletions(-)
 create mode 100644 Scope.php
 create mode 100644 VarNotInScope.php
 create mode 100644 tests/test_closure/.gitignore
 create mode 100644 tests/test_closure/code.php
 create mode 100644 tests/test_closure/test.tpl
 create mode 100644 tests/test_closure/want
 create mode 100644 tests/test_recursive/.gitignore
 create mode 100644 tests/test_recursive/code.php
 create mode 100644 tests/test_recursive/test.tpl
 create mode 100644 tests/test_recursive/want
 create mode 100644 tests/test_scoping/.gitignore
 create mode 100644 tests/test_scoping/code.php
 create mode 100644 tests/test_scoping/test.tpl
 create mode 100644 tests/test_scoping/want

diff --git a/STECore.php b/STECore.php
index 6bde63f..add09ad 100644
--- a/STECore.php
+++ b/STECore.php
@@ -10,19 +10,18 @@ class STECore {
 	private $tags;
 	private $storage_access;
 	private $cur_tpl_dir;
+	private $scope;
 	
 	/*
 	 * Variables: Public variables
 	 * 
 	 * $blocks - Associative array of blocks (see the language definition).
 	 * $blockorder - The order of the blocks (an array)
-	 * $vars - Associative array of all template variables. Use this to pass data to your templates.
 	 * $mute_runtime_errors - If true (default) a <RuntimeError> exception will result in no output from the tag, if false a error message will be written to output.
 	 * $fatal_error_on_missing_tag - If true, STE will throw a <FatalRuntimeError> if a tag was called that was not registered, otherwise (default) a regular <RuntimeError> will be thrown and automatically handled by STE (see <$mute_runtime_errors>).
 	 */
 	public $blocks;
 	public $blockorder;
-	public $vars;
 	public $mute_runtime_errors = true;
 	public $fatal_error_on_missing_tag = false;
 	
@@ -36,9 +35,10 @@ class STECore {
 		$this->storage_access = $storage_access;
 		$this->cur_tpl_dir = "/";
 		STEStandardLibrary::_register_lib($this);
-		$this->vars = array();
 		$this->blockorder = array();
 		$this->blocks = array();
+		
+		$this->set_scope(new Scope(array()));
 	}
 	
 	/*
@@ -140,46 +140,11 @@ class STECore {
 	 * Returns:
 	 * 	A Reference to the variable.
 	 */
-	
 	public function &get_var_reference($name, $create_if_not_exist) {
-		$ref = &$this->_get_var_reference($this->vars, $name, $create_if_not_exist);
+		$ref = &$this->scope->get_var_reference($name, $create_if_not_exist);
 		return $ref;
 	}
 	
-	private function &_get_var_reference(&$from, $name, $create_if_not_exist) {
-		$nullref = NULL;
-		
-		$bracket_open = strpos($name, "[");
-		if($bracket_open === false) {
-			if(isset($from[$name]) or $create_if_not_exist) {
-				$ref = &$from[$name];
-				return $ref;
-			} else {
-				return $nullref;
-			}
-		} else {
-			$bracket_close = strpos($name, "]", $bracket_open);
-			if($bracket_close === false) {
-				throw new RuntimeError("Invalid varname \"$name\". Missing closing \"]\".");
-			}
-			$varname = substr($name, 0, $bracket_open);
-			$name    = substr($name, $bracket_open + 1, $bracket_close - $bracket_open - 1) . substr($name, $bracket_close + 1);
-			if(!is_array($from[$varname])) {
-				if($create_if_not_exist) {
-					$from[$varname] = array();
-				} else {
-					return $nullref;
-				}
-			}
-			try {
-				$ref = &$this->_get_var_reference($from[$varname], $name, $create_if_not_exist);
-				return $ref;
-			} catch(Exception $e) {
-				throw new RuntimeError("Invalid varname \"$name\". Missing closing \"]\".");
-			}
-		}
-	}
-	
 	/*
 	 * Function: set_var_by_name
 	 * Set a template variable by its name.
@@ -193,8 +158,11 @@ class STECore {
 	 * 	<RuntimeError> if the variable name can not be parsed (e.g. unbalanced brackets).
 	 */
 	public function set_var_by_name($name, $val) {
-		$ref = &$this->_get_var_reference($this->vars, $name, true);
-		$ref = $val;
+		$this->scope->set_var_by_name($name, $val);
+	}
+	
+	public function set_local_var($name, $val) {
+		$this->scope->set_local_var($name, $val);
 	}
 	
 	/*
@@ -212,8 +180,7 @@ class STECore {
 	 * 	The variables value.
 	 */
 	public function get_var_by_name($name) {
-		$ref = $this->_get_var_reference($this->vars, $name, false);
-		return $ref === NULL ? "" : $ref;
+		return $this->scope->get_var_by_name($name);
 	}
 	
 	/*
@@ -297,4 +264,65 @@ class STECore {
 	public function evalbool($txt) {
 		return trim($txt . "") != "";
 	}
+	
+	public function get_scope() {
+		return $this->scope;
+	}
+	
+	public function set_scope($scope) {
+		$this->scope = $scope;
+	}
+	
+	public function make_closure($fx) {
+		$bound_scope = $this->scope;
+		return function() use($bound_scope, $fx) {
+			$args = func_get_args();
+			$ste = $args[0];
+			
+			$prev = $ste->get_scope();
+			$scope = $bound_scope->new_subscope();
+			$ste->set_scope($scope);
+			
+			try {
+				$result = call_user_func_array($fx, $args);
+				$ste->set_scope($prev);
+				return $result;
+			} catch(\Exception $e) {
+				$ste->set_scope($prev);
+				throw $e;
+			}
+		};
+	}
+	
+	public function __get($name) {
+		if($name === "vars") {
+			return $this->scope;
+		}
+		
+		$trace = debug_backtrace();
+		trigger_error(
+			'Undefined property via __get(): ' . $name .
+			' in ' . $trace[0]['file'] .
+			' on line ' . $trace[0]['line'],
+			E_USER_NOTICE);
+		return NULL;
+	}
+	
+	public function __set($name, $val) {
+		if($name !== "vars") {
+			$trace = debug_backtrace();
+			trigger_error(
+				'Undefined property via __set(): ' . $name .
+				' in ' . $trace[0]['file'] .
+				' on line ' . $trace[0]['line'],
+				E_USER_NOTICE);
+			return;
+		}
+		
+		if(is_array($val)) {
+			foreach($val as $k => $v) {
+				$this->scope[$k] = $v;
+			}
+		}
+	}
 }
diff --git a/Scope.php b/Scope.php
new file mode 100644
index 0000000..53566ed
--- /dev/null
+++ b/Scope.php
@@ -0,0 +1,187 @@
+<?php
+
+namespace kch42\ste;
+
+class Scope implements \ArrayAccess {
+	private $parent = NULL;
+	private $vars = array();
+	
+	private static function parse_name($name) {
+		$remain = $name;
+		$fields = array();
+		
+		while($remain !== "") {
+			$br_open = strpos($remain, '[');
+			if($br_open === false) {
+				$fields[] = $remain;
+				break;
+			}
+			
+			$br_close = strpos($remain, ']', $br_open);
+			if($br_close === false) {
+				throw new RuntimeError("Invalid varname \"$name\". Missing closing \"]\".");
+			}
+			
+			$fields[] = substr($remain, 0, $br_open);
+			
+			$field = substr($remain, $br_open+1, $br_close-$br_open-1);
+			$more = substr($remain, $br_close+1);
+			
+			if(strpos($field, '[') !== false) {
+				throw new RuntimeError("A variable field must not contain a '[' character.");
+			}
+			
+			if((strlen($more) > 0) && ($more[0] !== '[')) {
+				// TODO: better error message, not very non-programmer friendly...
+				throw new RuntimeError("A variable name must be of format name('[' name ']')*.");
+			}
+			
+			$remain = $field . $more;
+		}
+		
+		return $fields;
+	}
+	
+	private function &get_topvar_reference($name, $localonly) {
+		if(array_key_exists($name, $this->vars)) {
+			$ref = &$this->vars[$name];
+			return $ref;
+		}
+		
+		if((!$localonly) && ($this->parent !== NULL)) {
+			$ref = &$this->parent->get_topvar_reference($name, $localonly);
+			return $ref;
+		}
+
+		throw new VarNotInScope();
+	}
+	
+	/*
+	 * Function: get_var_reference
+	 * Get a reference to a template variable using a variable name.
+	 * This can be used, if your custom tag takes a variable name as a parameter.
+	 * 
+	 * Parameters:
+	 * 	$name - The variables name.
+	 * 	$create_if_not_exist - Should the variable be created, if it does not exist? Otherwise NULL will be returned, if the variable does not exist.
+	 * 
+	 * Throws:
+	 * 	<RuntimeError> if the variable name can not be parsed (e.g. unbalanced brackets).
+	 * 
+	 * Returns:
+	 * 	A Reference to the variable.
+	 */
+	public function &get_var_reference($name, $create_if_not_exist, $localonly=false) {
+		$nullref = NULL;
+		
+		$fields = self::parse_name($name);
+		if(count($fields) == 0) {
+			return $nullref; // TODO: or should we throw an exception here?
+		}
+		
+		$first = $fields[0];
+		
+		$ref = NULL;
+		try {
+			$ref = &$this->get_topvar_reference($first, $localonly);
+		} catch(VarNotInScope $e) {
+			if($create_if_not_exist) {
+				$this->vars[$first] = (count($fields) > 0) ? array() : "";
+				$ref = &$this->vars[$first];
+			} else {
+				return $nullref;
+			}
+		}
+		
+		for($i = 1; $i < count($fields); $i++) {
+			$field = $fields[$i];
+			
+			if(!is_array($ref)) {
+				return $nullref;
+			}
+			
+			if(!array_key_exists($field, $ref)) {
+				if(!$create_if_not_exist) {
+					return $nullref;
+				}
+				
+				if($i < count($fields) - 1) {
+					$ref[$field] = array();
+				} else {
+					$ref[$field] = "";
+				}
+			}
+			
+			$ref = &$ref[$field];
+		}
+		
+		return $ref;
+	}
+	
+	/*
+	 * Function: set_var_by_name
+	 * Set a template variable by its name.
+	 * This can be used, if your custom tag takes a variable name as a parameter.
+	 * 
+	 * Parameters:
+	 * 	$name - The variables name.
+	 * 	$val - The new value.
+	 * 
+	 * Throws:
+	 * 	<RuntimeError> if the variable name can not be parsed (e.g. unbalanced brackets).
+	 */
+	public function set_var_by_name($name, $val) {
+		$ref = &$this->get_var_reference($name, true);
+		$ref = $val;
+	}
+	
+	public function set_local_var($name, $val) {
+		$ref = &$this->get_var_reference($name, true, true);
+		$ref = $val;
+	}
+	
+	/*
+	 * Function: get_var_by_name
+	 * Get a template variable by its name.
+	 * This can be used, if your custom tag takes a variable name as a parameter.
+	 * 
+	 * Parameters:
+	 * 	$name - The variables name.
+	 * 
+	 * Throws:
+	 * 	<RuntimeError> if the variable name can not be parsed (e.g. unbalanced brackets).
+	 * 
+	 * Returns:
+	 * 	The variables value.
+	 */
+	public function get_var_by_name($name) {
+		$ref = $this->get_var_reference($name, false);
+		return $ref === NULL ? "" : $ref;
+	}
+	
+	public function new_subscope() {
+		$o = new self();
+		$o->parent = $this;
+		return $o;
+	}
+	
+	/* implementing ArrayAccess */
+	
+	public function offsetSet($offset, $value) {
+		$this->set_var_by_name($offset, $value);
+	}
+	public function offsetGet($offset) {
+		return $this->get_var_by_name($offset);
+	}
+	public function offsetExists($offset) {
+		try {
+			$this->get_topvar_reference($offset);
+			return true;
+		} catch(VarNotInScope $e) {
+			return false;
+		}
+	}
+	public function offsetUnset($offset) {
+		unset($this->vars[$offset]);
+	}
+}
diff --git a/Transcompiler.php b/Transcompiler.php
index 8b52fa2..b92663c 100644
--- a/Transcompiler.php
+++ b/Transcompiler.php
@@ -295,7 +295,7 @@ class Transcompiler {
 					throw new ParseCompileError("self::Transcompile Error: name missing in <ste:mktag>.", $ast->tpl, $ast->offset);
 				}
 				
-				$fxbody = "\$outputstack = array(''); \$outputstack_i = 0;\$ste->vars['_tag_parameters'] = \$params;\n";
+				$fxbody = "\$outputstack = array(''); \$outputstack_i = 0;\$ste->set_local_var('_tag_parameters', \$params);\n";
 				
 				list($tagname, $tagname_pre) = self::_transcompile($ast->params["name"], true);
 				
@@ -312,7 +312,7 @@ class Transcompiler {
 				$fxbody .= self::_transcompile($ast->sub);
 				$fxbody .= "return array_pop(\$outputstack);";
 				
-				$code .= "\$tag_fx = function(\$ste, \$params, \$sub)" . $usemandatory . "\n{\n" . self::indent_code($fxbody) . "\n};\n";
+				$code .= "\$tag_fx = \$ste->make_closure(function(\$ste, \$params, \$sub)" . $usemandatory . "\n{\n" . self::indent_code($fxbody) . "\n});\n";
 				$code .= $tagname_pre;
 				$code .= "\$ste->register_tag($tagname, \$tag_fx);\n";
 				
@@ -394,7 +394,7 @@ class Transcompiler {
 					}
 					
 					$code .= "\$outputstack[\$outputstack_i] .= \$ste->call_tag('" . Misc::escape_text($node->name) . "', \$${paramarray}, ";
-					$code .= empty($node->sub) ? "function(\$ste) { return ''; }" : self::transcompile($node->sub);
+					$code .= empty($node->sub) ? "function(\$ste) { return ''; }" : ("\$ste->make_closure(" . self::transcompile($node->sub) . ")");
 					$code .= ");\n";
 				}
 			}
diff --git a/VarNotInScope.php b/VarNotInScope.php
new file mode 100644
index 0000000..179d07a
--- /dev/null
+++ b/VarNotInScope.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace kch42\ste;
+
+class VarNotInScope extends \Exception {}
diff --git a/ste.php b/ste.php
index 6647098..7e40fae 100644
--- a/ste.php
+++ b/ste.php
@@ -30,6 +30,9 @@ require_once(__DIR__ . "/Calc.php");
 require_once(__DIR__ . "/Parser.php");
 require_once(__DIR__ . "/Transcompiler.php");
 
+require_once(__DIR__ . "/VarNotInScope.php");
+require_once(__DIR__ . "/Scope.php");
+
 require_once(__DIR__ . "/STEStandardLibrary.php");
 require_once(__DIR__ . "/STECore.php");
 
diff --git a/tests/test_closure/.gitignore b/tests/test_closure/.gitignore
new file mode 100644
index 0000000..de2a41b
--- /dev/null
+++ b/tests/test_closure/.gitignore
@@ -0,0 +1,3 @@
+have
+*.ast
+*.transc.php
diff --git a/tests/test_closure/code.php b/tests/test_closure/code.php
new file mode 100644
index 0000000..de8c553
--- /dev/null
+++ b/tests/test_closure/code.php
@@ -0,0 +1,5 @@
+<?php
+
+function test_func($ste) {
+	
+}
diff --git a/tests/test_closure/test.tpl b/tests/test_closure/test.tpl
new file mode 100644
index 0000000..c13bd5a
--- /dev/null
+++ b/tests/test_closure/test.tpl
@@ -0,0 +1,8 @@
+<ste:mktag name="initfoo">
+	<ste:set var="x"><ste:tagcontent /></ste:set>
+	<ste:mktag name="foo">
+		<ste:calc>$x + <ste:tagcontent /></ste:calc>
+	</ste:mktag>
+</ste:mktag>
+<ste:initfoo>10</ste:initfoo>
+<ste:foo>20</ste:foo>
\ No newline at end of file
diff --git a/tests/test_closure/want b/tests/test_closure/want
new file mode 100644
index 0000000..64bb6b7
--- /dev/null
+++ b/tests/test_closure/want
@@ -0,0 +1 @@
+30
diff --git a/tests/test_mktag/test.tpl b/tests/test_mktag/test.tpl
index c381ef4..c446206 100644
--- a/tests/test_mktag/test.tpl
+++ b/tests/test_mktag/test.tpl
@@ -1,11 +1,10 @@
 <ste:mktag name="double"><ste:calc>2 * <ste:tagcontent /></ste:calc></ste:mktag>
 <ste:mktag name="foo" mandatory="a|b">
-	<ste:set var="b">$_tag_parameters[b]</ste:set><ste:comment>Ugly hack, since STE does no scoping...</ste:comment>
 	<ste:for counter="i" start="0" stop="$_tag_parameters[a]">
 		<ste:if>
 			<ste:even>$i</ste:even>
 			<ste:then><ste:double>$i</ste:double></ste:then>
-			<ste:else>$b</ste:else>
+			<ste:else>$_tag_parameters[b]</ste:else>
 		</ste:if>
 	</ste:for>
 </ste:mktag>
diff --git a/tests/test_recursive/.gitignore b/tests/test_recursive/.gitignore
new file mode 100644
index 0000000..de2a41b
--- /dev/null
+++ b/tests/test_recursive/.gitignore
@@ -0,0 +1,3 @@
+have
+*.ast
+*.transc.php
diff --git a/tests/test_recursive/code.php b/tests/test_recursive/code.php
new file mode 100644
index 0000000..4ca3852
--- /dev/null
+++ b/tests/test_recursive/code.php
@@ -0,0 +1,5 @@
+<?php
+
+function test_func($ste) {
+	$ste->mute_runtime_errors = false;
+}
diff --git a/tests/test_recursive/test.tpl b/tests/test_recursive/test.tpl
new file mode 100644
index 0000000..bea3934
--- /dev/null
+++ b/tests/test_recursive/test.tpl
@@ -0,0 +1,11 @@
+<ste:mktag name="fac" mandatory="n">
+	<ste:if>
+		~{$_tag_parameters[n]|eq|0}
+		<ste:then>1</ste:then>
+		<ste:else>
+			<ste:set var="nextn"><ste:calc>$_tag_parameters[n] - 1</ste:calc></ste:set>
+			<ste:calc><ste:fac n="$nextn" /> * $_tag_parameters[n]</ste:calc>
+		</ste:else>
+	</ste:if>
+</ste:mktag>
+<ste:fac n="10" />
\ No newline at end of file
diff --git a/tests/test_recursive/want b/tests/test_recursive/want
new file mode 100644
index 0000000..3fbd4a8
--- /dev/null
+++ b/tests/test_recursive/want
@@ -0,0 +1 @@
+3628800
diff --git a/tests/test_scoping/.gitignore b/tests/test_scoping/.gitignore
new file mode 100644
index 0000000..de2a41b
--- /dev/null
+++ b/tests/test_scoping/.gitignore
@@ -0,0 +1,3 @@
+have
+*.ast
+*.transc.php
diff --git a/tests/test_scoping/code.php b/tests/test_scoping/code.php
new file mode 100644
index 0000000..de8c553
--- /dev/null
+++ b/tests/test_scoping/code.php
@@ -0,0 +1,5 @@
+<?php
+
+function test_func($ste) {
+	
+}
diff --git a/tests/test_scoping/test.tpl b/tests/test_scoping/test.tpl
new file mode 100644
index 0000000..25a46e7
--- /dev/null
+++ b/tests/test_scoping/test.tpl
@@ -0,0 +1,6 @@
+<ste:mktag name="foo">
+	<ste:set var="bla">!</ste:set>
+</ste:mktag>
+
+<ste:foo />
+$bla
\ No newline at end of file
diff --git a/tests/test_scoping/want b/tests/test_scoping/want
new file mode 100644
index 0000000..e69de29
-- 
cgit v1.2.3-54-g00ecf