@@ -3,10 +3,10 @@ require_once dirname(__FILE__) . '/tree.php'; class FuTreeDSLInterpreter extends Fu { - var $body, $defs = array(), $output; + var $body, $defs = array(), $outer, $output; function evaluate($node) { - if ($this->defed($name = $node->value())) { return $this->defs[$name]; } + if ($scope = $this->scopeWithDef($name = $node->value())) { return $scope->defs[$name]; } if ($incomprisable = $this->incomprisable($name)) { return $incomprisable->call(array($node->firstInner())); } throw err('Undefined symbol')->ofName($name); } @@ -32,7 +32,7 @@ class FuTreeDSLInterpreter extends Fu { function symNull() { return null; } function symNode($node) { return $node; } function symStr($node) { return $node->value(); } - function symFn($node) { return with(new $this)->body($node); } + function symFn($node) { return with(new $this)->outer($this)->body($node); } function symNodeOf($node) { return n($this->evaluate($node)); } function symExpr($node) { return eval('return ' . join(NL, $node->values()) . ';'); } function symCall($node) { return $this->evaluate($node)->output($this->output)->call(); } @@ -41,10 +41,15 @@ class FuTreeDSLInterpreter extends Fu { function incomprisable($name) { if (method_exists($this, $method = 'sym'.$name)) { return $this->method($method); } } - function defed($name) { return array_key_exists($name, $this->defs); } + // Retrieves the first instance, looking back through outers, that has `$name` defined. + function scopeWithDef($name) { + if (array_key_exists($name, $this->defs)) { return $this; } + if ($this->outer) { return $this->outer->{__FUNCTION__}($name); } + return false; } + // Creates a definition. function symDef($node) { - if ($this->defed($name = $node->value())) { throw err('Redefinition')->of($name); } + if ($this->scopeWithDef($name = $node->value())) { throw err('Redefinition')->of($name); } return $this->defs[$name] = ($v = $node->next()) ? $this->evaluate($v) : null; } function symIf($node) { lib/tree_dsl.php @@ -122,4 +122,22 @@ class DefSpec extends DSLInterpreterSpec { _($err->of())->shouldBe($this->undefed()->value()); } } function _should_allow_redef_of_incomprisables() { - _($this->subj->run(nList(n('def', n('if'), n('true')), n('if'))))->shouldBe(true); } } \ No newline at end of file + _($this->subj->run(nList(n('def', n('if'), n('true')), n('if'))))->shouldBe(true); } } + + +class LexicalScopeSpec extends DSLInterpreterSpec { + + function _defs_in_fns_should_not_exist_outside() { + $tree = nList(n('call', n('fn', n('def', $this->undefed(), n('true')))), $this->undefed()); + if (_($err = rescue(array($this->subj, 'run'), array($tree)))->shouldNotBe(null)) { + _($err->msg())->shouldBe('Undefined symbol'); + _($err->ofName())->shouldBe($this->undefed()->value()); } } + + function _defs_outside_fns_should_exist_inside() { + $tree = nList(n('def', $this->undefed(), n('true')), n('call', n('fn', $this->undefed()))); + _($this->subj->run($tree))->shouldBe(true); } + + function _defs_outside_multiple_fns_should_exist_inside() { + $tree = nList(n('def', $this->undefed(), n('true')), + n('call', n('fn', n('call', n('fn', $this->undefed()))))); + _($this->subj->run($tree))->shouldBe(true); } } \ No newline at end of file spec/tree_dsl.php ccdf7d1d37f6297b1e301d566b88ba1ffb9271ae ole oliver.saunders@gmail.com http://github.com/olliesaunders/fluidics/commit/d4c30959f6eef96079eaf21be65659a3a448a91c d4c30959f6eef96079eaf21be65659a3a448a91c 2009-11-09T05:43:43-08:00 2009-11-09T05:43:43-08:00 Tree DSL: Now has lexical scope. 66c07696957aa042bd3e473f564c611298fa623b ole oliver.saunders@gmail.com