start:
      top_statement_list { $$ = $this->handleNamespaces($1); }
;

top_statement_list:
      top_statement_list top_statement { pushNormalizing($1, $2); }
    | /* empty */ { init(); }
;

namespace_name_parts:
      T_STRING { init($1); }
    | namespace_name_parts T_NS_SEPARATOR T_STRING { push($1, $3); }
;

namespace_name:
      namespace_name_parts { $$ = Name[$1]; }
;

top_statement:
      statement { $$ = $1; }
    | function_declaration_statement { $$ = $1; }
    | class_declaration_statement { $$ = $1; }
    | T_HALT_COMPILER { $$ = Stmt\HaltCompiler[$this->lexer->handleHaltCompiler()]; }
    | T_NAMESPACE namespace_name ';' { $$ = Stmt\Namespace_[$2, null]; }
    | T_NAMESPACE namespace_name '{' top_statement_list '}' { $$ = Stmt\Namespace_[$2, $4]; }
    | T_NAMESPACE '{' top_statement_list '}' { $$ = Stmt\Namespace_[null,     $3]; }
    | T_USE use_declarations ';' { $$ = Stmt\Use_[$2, Stmt\Use_::TYPE_NORMAL]; }
    | T_USE T_FUNCTION use_declarations ';' { $$ = Stmt\Use_[$3, Stmt\Use_::TYPE_FUNCTION]; }
    | T_USE T_CONST use_declarations ';' { $$ = Stmt\Use_[$3, Stmt\Use_::TYPE_CONSTANT]; }
    | T_CONST constant_declaration_list ';' { $$ = Stmt\Const_[$2]; }
;

use_declarations:
      use_declarations ',' use_declaration { push($1, $3); }
    | use_declaration { init($1); }
;

use_declaration:
      namespace_name { $$ = Stmt\UseUse[$1, null]; }
    | namespace_name T_AS T_STRING { $$ = Stmt\UseUse[$1, $3]; }
    | T_NS_SEPARATOR namespace_name { $$ = Stmt\UseUse[$2, null]; }
    | T_NS_SEPARATOR namespace_name T_AS T_STRING { $$ = Stmt\UseUse[$2, $4]; }
;

constant_declaration_list:
      constant_declaration_list ',' constant_declaration { push($1, $3); }
    | constant_declaration { init($1); }
;

constant_declaration:
      T_STRING '=' static_scalar { $$ = Node\Const_[$1, $3]; }
;

inner_statement_list:
      inner_statement_list inner_statement { pushNormalizing($1, $2); }
    | /* empty */ { init(); }
;

inner_statement:
      statement { $$ = $1; }
    | function_declaration_statement { $$ = $1; }
    | class_declaration_statement { $$ = $1; }
    | T_HALT_COMPILER { throw new Error('__HALT_COMPILER() can only be used from the outermost scope', attributes()); }
;

statement:
      '{' inner_statement_list '}' { $$ = $2; }
    | T_IF parentheses_expr statement elseif_list else_single { $$ = Stmt\If_[$2, [stmts: toArray($3), elseifs: $4, else: $5]]; }
    | T_IF parentheses_expr ':' inner_statement_list new_elseif_list new_else_single T_ENDIF ';' { $$ = Stmt\If_[$2, [stmts: $4, elseifs: $5, else: $6]]; }
    | T_WHILE parentheses_expr while_statement { $$ = Stmt\While_[$2, $3]; }
    | T_DO statement T_WHILE parentheses_expr ';' { $$ = Stmt\Do_   [$4, toArray($2)]; }
    | T_FOR '(' for_expr ';' for_expr ';' for_expr ')' for_statement { $$ = Stmt\For_[[init: $3, cond: $5, loop: $7, stmts: $9]]; }
    | T_SWITCH parentheses_expr switch_case_list { $$ = Stmt\Switch_[$2, $3]; }
    | T_BREAK ';' { $$ = Stmt\Break_[null]; }
    | T_BREAK expr ';' { $$ = Stmt\Break_[$2]; }
    | T_CONTINUE ';' { $$ = Stmt\Continue_[null]; }
    | T_CONTINUE expr ';' { $$ = Stmt\Continue_[$2]; }
    | T_RETURN ';' { $$ = Stmt\Return_[null]; }
    | T_RETURN expr ';' { $$ = Stmt\Return_[$2]; }
    | yield_expr ';' { $$ = $1; }
    | T_GLOBAL global_var_list ';' { $$ = Stmt\Global_[$2]; }
    | T_STATIC static_var_list ';' { $$ = Stmt\Static_[$2]; }
    | T_ECHO expr_list ';' { $$ = Stmt\Echo_[$2]; }
    | T_INLINE_HTML { $$ = Stmt\InlineHTML[$1]; }
    | expr ';' { $$ = $1; }
    | T_UNSET '(' variables_list ')' ';' { $$ = Stmt\Unset_[$3]; }
    | T_FOREACH '(' expr T_AS foreach_variable ')' foreach_statement { $$ = Stmt\Foreach_[$3, $5[0], [keyVar: null, byRef: $5[1], stmts: $7]]; }
    | T_FOREACH '(' expr T_AS variable T_DOUBLE_ARROW foreach_variable ')' foreach_statement { $$ = Stmt\Foreach_[$3, $7[0], [keyVar: $5, byRef: $7[1], stmts: $9]]; }
    | T_DECLARE '(' declare_list ')' declare_statement { $$ = Stmt\Declare_[$3, $5]; }
    | ';' { $$ = array(); /* means: no statement */ }
    | T_TRY '{' inner_statement_list '}' catches optional_finally { $$ = Stmt\TryCatch[$3, $5, $6]; }
    | T_THROW expr ';' { $$ = Stmt\Throw_[$2]; }
    | T_GOTO T_STRING ';' { $$ = Stmt\Goto_[$2]; }
    | T_STRING ':' { $$ = Stmt\Label[$1]; }
    | error { $$ = array(); /* means: no statement */ }
;

catches:
      /* empty */ { init(); }
    | catches catch { push($1, $2); }
;

catch:
      T_CATCH '(' name T_VARIABLE ')' '{' inner_statement_list '}' { $$ = Stmt\Catch_[$3, parseVar($4), $7]; }
;

optional_finally:
      /* empty */ { $$ = null; }
    | T_FINALLY '{' inner_statement_list '}' { $$ = $3; }
;

variables_list:
      variable { init($1); }
    | variables_list ',' variable { push($1, $3); }
;

optional_ref:
      /* empty */ { $$ = false; }
    | '&' { $$ = true; }
;

optional_ellipsis:
      /* empty */ { $$ = false; }
    | T_ELLIPSIS { $$ = true; }
;

function_declaration_statement:
      T_FUNCTION optional_ref T_STRING '(' parameter_list ')' optional_return_type '{' inner_statement_list '}' { $$ = Stmt\Function_[$3, [byRef: $2, params: $5, returnType: $7, stmts: $9]]; }
;

class_declaration_statement:
      class_entry_type T_STRING extends_from implements_list '{' class_statement_list '}' { $$ = Stmt\Class_[$2, [type: $1, extends: $3, implements: $4, stmts: $6]]; }
    | T_INTERFACE T_STRING interface_extends_list '{' class_statement_list '}' { $$ = Stmt\Interface_[$2, [extends: $3, stmts: $5]]; }
    | T_TRAIT T_STRING '{' class_statement_list '}' { $$ = Stmt\Trait_[$2, $4]; }
;

class_entry_type:
      T_CLASS { $$ = 0; }
    | T_ABSTRACT T_CLASS { $$ = Stmt\Class_::MODIFIER_ABSTRACT; }
    | T_FINAL T_CLASS { $$ = Stmt\Class_::MODIFIER_FINAL; }
;

extends_from:
      /* empty */ { $$ = null; }
    | T_EXTENDS name { $$ = $2; }
;

interface_extends_list:
      /* empty */ { $$ = array(); }
    | T_EXTENDS name_list { $$ = $2; }
;

implements_list:
      /* empty */ { $$ = array(); }
    | T_IMPLEMENTS name_list { $$ = $2; }
;

name_list:
      name { init($1); }
    | name_list ',' name { push($1, $3); }
;

for_statement:
      statement { $$ = toArray($1); }
    | ':' inner_statement_list T_ENDFOR ';' { $$ = $2; }
;

foreach_statement:
      statement { $$ = toArray($1); }
    | ':' inner_statement_list T_ENDFOREACH ';' { $$ = $2; }
;

declare_statement:
      statement { $$ = toArray($1); }
    | ':' inner_statement_list T_ENDDECLARE ';' { $$ = $2; }
;

declare_list:
      declare_list_element { init($1); }
    | declare_list ',' declare_list_element { push($1, $3); }
;

declare_list_element:
      T_STRING '=' static_scalar { $$ = Stmt\DeclareDeclare[$1, $3]; }
;

switch_case_list:
      '{' case_list '}' { $$ = $2; }
    | '{' ';' case_list '}' { $$ = $3; }
    | ':' case_list T_ENDSWITCH ';' { $$ = $2; }
    | ':' ';' case_list T_ENDSWITCH ';' { $$ = $3; }
;

case_list:
      /* empty */ { init(); }
    | case_list case { push($1, $2); }
;

case:
      T_CASE expr case_separator inner_statement_list { $$ = Stmt\Case_[$2, $4]; }
    | T_DEFAULT case_separator inner_statement_list { $$ = Stmt\Case_[null, $3]; }
;

case_separator:
      ':'
    | ';'
;

while_statement:
      statement { $$ = toArray($1); }
    | ':' inner_statement_list T_ENDWHILE ';' { $$ = $2; }
;

elseif_list:
      /* empty */ { init(); }
    | elseif_list elseif { push($1, $2); }
;

elseif:
      T_ELSEIF parentheses_expr statement { $$ = Stmt\ElseIf_[$2, toArray($3)]; }
;

new_elseif_list:
      /* empty */ { init(); }
    | new_elseif_list new_elseif { push($1, $2); }
;

new_elseif:
      T_ELSEIF parentheses_expr ':' inner_statement_list { $$ = Stmt\ElseIf_[$2, $4]; }
;

else_single:
      /* empty */ { $$ = null; }
    | T_ELSE statement { $$ = Stmt\Else_[toArray($2)]; }
;

new_else_single:
      /* empty */ { $$ = null; }
    | T_ELSE ':' inner_statement_list { $$ = Stmt\Else_[$3]; }
;

foreach_variable:
      variable { $$ = array($1, false); }
    | '&' variable { $$ = array($2, true); }
    | list_expr { $$ = array($1, false); }
;

parameter_list:
      non_empty_parameter_list { $$ = $1; }
    | /* empty */ { $$ = array(); }
;

non_empty_parameter_list:
      parameter { init($1); }
    | non_empty_parameter_list ',' parameter { push($1, $3); }
;

parameter:
      optional_param_type optional_ref optional_ellipsis T_VARIABLE { $$ = Node\Param[parseVar($4), null, $1, $2, $3]; }
    | optional_param_type optional_ref optional_ellipsis T_VARIABLE '=' static_scalar { $$ = Node\Param[parseVar($4), $6, $1, $2, $3]; }
;

type:
      name { $$ = $1; }
    | T_ARRAY { $$ = 'array'; }
    | T_CALLABLE { $$ = 'callable'; }
;

optional_param_type:
      /* empty */ { $$ = null; }
    | type { $$ = $1; }
;

optional_return_type:
      /* empty */ { $$ = null; }
    | ':' type { $$ = $2; }
;

argument_list:
      '(' ')' { $$ = array(); }
    | '(' non_empty_argument_list ')' { $$ = $2; }
    | '(' yield_expr ')' { $$ = array(Node\Arg[$2, false, false]); }
;

non_empty_argument_list:
      argument { init($1); }
    | non_empty_argument_list ',' argument { push($1, $3); }
;

argument:
      expr { $$ = Node\Arg[$1, false, false]; }
    | '&' variable { $$ = Node\Arg[$2, true, false]; }
    | T_ELLIPSIS expr { $$ = Node\Arg[$2, false, true]; }
;

global_var_list:
      global_var_list ',' global_var { push($1, $3); }
    | global_var { init($1); }
;

global_var:
      T_VARIABLE { $$ = Expr\Variable[parseVar($1)]; }
    | '$' variable { $$ = Expr\Variable[$2]; }
    | '$' '{' expr '}' { $$ = Expr\Variable[$3]; }
;

static_var_list:
      static_var_list ',' static_var { push($1, $3); }
    | static_var { init($1); }
;

static_var:
      T_VARIABLE { $$ = Stmt\StaticVar[parseVar($1), null]; }
    | T_VARIABLE '=' static_scalar { $$ = Stmt\StaticVar[parseVar($1), $3]; }
;

class_statement_list:
      class_statement_list class_statement { push($1, $2); }
    | /* empty */ { init(); }
;

class_statement:
      variable_modifiers property_declaration_list ';' { $$ = Stmt\Property[$1, $2]; }
    | T_CONST constant_declaration_list ';' { $$ = Stmt\ClassConst[$2]; }
    | method_modifiers T_FUNCTION optional_ref T_STRING '(' parameter_list ')' optional_return_type method_body { $$ = Stmt\ClassMethod[$4, [type: $1, byRef: $3, params: $6, returnType: $8, stmts: $9]]; }
    | T_USE name_list trait_adaptations { $$ = Stmt\TraitUse[$2, $3]; }
;

trait_adaptations:
      ';' { $$ = array(); }
    | '{' trait_adaptation_list '}' { $$ = $2; }
;

trait_adaptation_list:
      /* empty */ { init(); }
    | trait_adaptation_list trait_adaptation { push($1, $2); }
;

trait_adaptation:
      trait_method_reference_fully_qualified T_INSTEADOF name_list ';' { $$ = Stmt\TraitUseAdaptation\Precedence[$1[0], $1[1], $3]; }
    | trait_method_reference T_AS member_modifier T_STRING ';' { $$ = Stmt\TraitUseAdaptation\Alias[$1[0], $1[1], $3, $4]; }
    | trait_method_reference T_AS member_modifier ';' { $$ = Stmt\TraitUseAdaptation\Alias[$1[0], $1[1], $3, null]; }
    | trait_method_reference T_AS T_STRING ';' { $$ = Stmt\TraitUseAdaptation\Alias[$1[0], $1[1], null, $3]; }
;

trait_method_reference_fully_qualified:
      name T_PAAMAYIM_NEKUDOTAYIM T_STRING { $$ = array($1, $3); }
;

trait_method_reference:
      trait_method_reference_fully_qualified { $$ = $1; }
    | T_STRING { $$ = array(null, $1); }
;

method_body:
      ';' /* abstract method */ { $$ = null; }
    | '{' inner_statement_list '}' { $$ = $2; }
;

variable_modifiers:
      non_empty_member_modifiers { $$ = $1; }
    | T_VAR { $$ = 0; }
;

method_modifiers:
      /* empty */ { $$ = 0; }
    | non_empty_member_modifiers { $$ = $1; }
;

non_empty_member_modifiers:
      member_modifier { $$ = $1; }
    | non_empty_member_modifiers member_modifier { Stmt\Class_::verifyModifier($1, $2); $$ = $1 | $2; }
;

member_modifier:
      T_PUBLIC { $$ = Stmt\Class_::MODIFIER_PUBLIC; }
    | T_PROTECTED { $$ = Stmt\Class_::MODIFIER_PROTECTED; }
    | T_PRIVATE { $$ = Stmt\Class_::MODIFIER_PRIVATE; }
    | T_STATIC { $$ = Stmt\Class_::MODIFIER_STATIC; }
    | T_ABSTRACT { $$ = Stmt\Class_::MODIFIER_ABSTRACT; }
    | T_FINAL { $$ = Stmt\Class_::MODIFIER_FINAL; }
;

property_declaration_list:
      property_declaration { init($1); }
    | property_declaration_list ',' property_declaration { push($1, $3); }
;

property_declaration:
      T_VARIABLE { $$ = Stmt\PropertyProperty[parseVar($1), null]; }
    | T_VARIABLE '=' static_scalar { $$ = Stmt\PropertyProperty[parseVar($1), $3]; }
;

expr_list:
      expr_list ',' expr { push($1, $3); }
    | expr { init($1); }
;

for_expr:
      /* empty */ { $$ = array(); }
    | expr_list { $$ = $1; }
;

expr:
      variable { $$ = $1; }
    | list_expr '=' expr { $$ = Expr\Assign[$1, $3]; }
    | variable '=' expr { $$ = Expr\Assign[$1, $3]; }
    | variable '=' '&' variable { $$ = Expr\AssignRef[$1, $4]; }
    | variable '=' '&' new_expr { $$ = Expr\AssignRef[$1, $4]; }
    | new_expr { $$ = $1; }
    | T_CLONE expr { $$ = Expr\Clone_[$2]; }
    | variable T_PLUS_EQUAL expr { $$ = Expr\AssignOp\Plus      [$1, $3]; }
    | variable T_MINUS_EQUAL expr { $$ = Expr\AssignOp\Minus     [$1, $3]; }
    | variable T_MUL_EQUAL expr { $$ = Expr\AssignOp\Mul       [$1, $3]; }
    | variable T_DIV_EQUAL expr { $$ = Expr\AssignOp\Div       [$1, $3]; }
    | variable T_CONCAT_EQUAL expr { $$ = Expr\AssignOp\Concat    [$1, $3]; }
    | variable T_MOD_EQUAL expr { $$ = Expr\AssignOp\Mod       [$1, $3]; }
    | variable T_AND_EQUAL expr { $$ = Expr\AssignOp\BitwiseAnd[$1, $3]; }
    | variable T_OR_EQUAL expr { $$ = Expr\AssignOp\BitwiseOr [$1, $3]; }
    | variable T_XOR_EQUAL expr { $$ = Expr\AssignOp\BitwiseXor[$1, $3]; }
    | variable T_SL_EQUAL expr { $$ = Expr\AssignOp\ShiftLeft [$1, $3]; }
    | variable T_SR_EQUAL expr { $$ = Expr\AssignOp\ShiftRight[$1, $3]; }
    | variable T_POW_EQUAL expr { $$ = Expr\AssignOp\Pow       [$1, $3]; }
    | variable T_INC { $$ = Expr\PostInc[$1]; }
    | T_INC variable { $$ = Expr\PreInc [$2]; }
    | variable T_DEC { $$ = Expr\PostDec[$1]; }
    | T_DEC variable { $$ = Expr\PreDec [$2]; }
    | expr T_BOOLEAN_OR expr { $$ = Expr\BinaryOp\BooleanOr [$1, $3]; }
    | expr T_BOOLEAN_AND expr { $$ = Expr\BinaryOp\BooleanAnd[$1, $3]; }
    | expr T_LOGICAL_OR expr { $$ = Expr\BinaryOp\LogicalOr [$1, $3]; }
    | expr T_LOGICAL_AND expr { $$ = Expr\BinaryOp\LogicalAnd[$1, $3]; }
    | expr T_LOGICAL_XOR expr { $$ = Expr\BinaryOp\LogicalXor[$1, $3]; }
    | expr '|' expr { $$ = Expr\BinaryOp\BitwiseOr [$1, $3]; }
    | expr '&' expr { $$ = Expr\BinaryOp\BitwiseAnd[$1, $3]; }
    | expr '^' expr { $$ = Expr\BinaryOp\BitwiseXor[$1, $3]; }
    | expr '.' expr { $$ = Expr\BinaryOp\Concat    [$1, $3]; }
    | expr '+' expr { $$ = Expr\BinaryOp\Plus      [$1, $3]; }
    | expr '-' expr { $$ = Expr\BinaryOp\Minus     [$1, $3]; }
    | expr '*' expr { $$ = Expr\BinaryOp\Mul       [$1, $3]; }
    | expr '/' expr { $$ = Expr\BinaryOp\Div       [$1, $3]; }
    | expr '%' expr { $$ = Expr\BinaryOp\Mod       [$1, $3]; }
    | expr T_SL expr { $$ = Expr\BinaryOp\ShiftLeft [$1, $3]; }
    | expr T_SR expr { $$ = Expr\BinaryOp\ShiftRight[$1, $3]; }
    | expr T_POW expr { $$ = Expr\BinaryOp\Pow       [$1, $3]; }
    | '+' expr %prec T_INC { $$ = Expr\UnaryPlus [$2]; }
    | '-' expr %prec T_INC { $$ = Expr\UnaryMinus[$2]; }
    | '!' expr { $$ = Expr\BooleanNot[$2]; }
    | '~' expr { $$ = Expr\BitwiseNot[$2]; }
    | expr T_IS_IDENTICAL expr { $$ = Expr\BinaryOp\Identical     [$1, $3]; }
    | expr T_IS_NOT_IDENTICAL expr { $$ = Expr\BinaryOp\NotIdentical  [$1, $3]; }
    | expr T_IS_EQUAL expr { $$ = Expr\BinaryOp\Equal         [$1, $3]; }
    | expr T_IS_NOT_EQUAL expr { $$ = Expr\BinaryOp\NotEqual      [$1, $3]; }
    | expr T_SPACESHIP expr { $$ = Expr\BinaryOp\Spaceship     [$1, $3]; }
    | expr '<' expr { $$ = Expr\BinaryOp\Smaller       [$1, $3]; }
    | expr T_IS_SMALLER_OR_EQUAL expr { $$ = Expr\BinaryOp\SmallerOrEqual[$1, $3]; }
    | expr '>' expr { $$ = Expr\BinaryOp\Greater       [$1, $3]; }
    | expr T_IS_GREATER_OR_EQUAL expr { $$ = Expr\BinaryOp\GreaterOrEqual[$1, $3]; }
    | expr T_INSTANCEOF class_name_reference { $$ = Expr\Instanceof_[$1, $3]; }
    | parentheses_expr { $$ = $1; } /* we need a separate '(' new_expr ')' rule to avoid problems caused by a s/r conflict */
    | '(' new_expr ')' { $$ = $2; }
    | expr '?' expr ':' expr { $$ = Expr\Ternary[$1, $3,   $5]; }
    | expr '?' ':' expr { $$ = Expr\Ternary[$1, null, $4]; }
    | expr T_COALESCE expr { $$ = Expr\BinaryOp\Coalesce[$1, $3]; }
    | T_ISSET '(' variables_list ')' { $$ = Expr\Isset_[$3]; }
    | T_EMPTY '(' expr ')' { $$ = Expr\Empty_[$3]; }
    | T_INCLUDE expr { $$ = Expr\Include_[$2, Expr\Include_::TYPE_INCLUDE]; }
    | T_INCLUDE_ONCE expr { $$ = Expr\Include_[$2, Expr\Include_::TYPE_INCLUDE_ONCE]; }
    | T_EVAL parentheses_expr { $$ = Expr\Eval_[$2]; }
    | T_REQUIRE expr { $$ = Expr\Include_[$2, Expr\Include_::TYPE_REQUIRE]; }
    | T_REQUIRE_ONCE expr { $$ = Expr\Include_[$2, Expr\Include_::TYPE_REQUIRE_ONCE]; }
    | T_INT_CAST expr { $$ = Expr\Cast\Int_    [$2]; }
    | T_DOUBLE_CAST expr { $$ = Expr\Cast\Double  [$2]; }
    | T_STRING_CAST expr { $$ = Expr\Cast\String_ [$2]; }
    | T_ARRAY_CAST expr { $$ = Expr\Cast\Array_  [$2]; }
    | T_OBJECT_CAST expr { $$ = Expr\Cast\Object_ [$2]; }
    | T_BOOL_CAST expr { $$ = Expr\Cast\Bool_   [$2]; }
    | T_UNSET_CAST expr { $$ = Expr\Cast\Unset_  [$2]; }
    | T_EXIT exit_expr { $$ = Expr\Exit_        [$2]; }
    | '@' expr { $$ = Expr\ErrorSuppress[$2]; }
    | scalar { $$ = $1; }
    | array_expr { $$ = $1; }
    | scalar_dereference { $$ = $1; }
    | '`' backticks_expr '`' { $$ = Expr\ShellExec[$2]; }
    | T_PRINT expr { $$ = Expr\Print_[$2]; }
    | T_YIELD { $$ = Expr\Yield_[null, null]; }
    | T_YIELD_FROM expr { $$ = Expr\YieldFrom[$2]; }
    | T_FUNCTION optional_ref '(' parameter_list ')' lexical_vars optional_return_type '{' inner_statement_list '}' { $$ = Expr\Closure[[static: false, byRef: $2, params: $4, uses: $6, returnType: $7, stmts: $9]]; }
    | T_STATIC T_FUNCTION optional_ref '(' parameter_list ')' lexical_vars optional_return_type '{' inner_statement_list '}' { $$ = Expr\Closure[[static: true, byRef: $3, params: $5, uses: $7, returnType: $8, stmts: $10]]; }
;

parentheses_expr:
      '(' expr ')' { $$ = $2; }
    | '(' yield_expr ')' { $$ = $2; }
;

yield_expr:
      T_YIELD expr { $$ = Expr\Yield_[$2, null]; }
    | T_YIELD expr T_DOUBLE_ARROW expr { $$ = Expr\Yield_[$4, $2]; }
;

array_expr:
      T_ARRAY '(' array_pair_list ')' { $$ = Expr\Array_[$3]; }
    | '[' array_pair_list ']' { $$ = Expr\Array_[$2]; }
;

scalar_dereference:
      array_expr '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | T_CONSTANT_ENCAPSED_STRING '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[Scalar\String_[Scalar\String_::parse($1)], $3]; }
    | constant '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | scalar_dereference '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; } /* alternative array syntax missing intentionally */
;

anonymous_class:
      T_CLASS ctor_arguments extends_from implements_list '{' class_statement_list '}' { $$ = array(Stmt\Class_[null, [type: 0, extends: $3, implements: $4, stmts: $6]], $2); } new_expr: T_NEW class_name_reference ctor_arguments { $$ = Expr\New_[$2, $3]; }
    | T_NEW anonymous_class { list($class, $ctorArgs) = $2; $$ = Expr\New_[$class, $ctorArgs]; }
;

lexical_vars:
      /* empty */ { $$ = array(); }
    | T_USE '(' lexical_var_list ')' { $$ = $3; }
;

lexical_var_list:
      lexical_var { init($1); }
    | lexical_var_list ',' lexical_var { push($1, $3); }
;

lexical_var:
      optional_ref T_VARIABLE { $$ = Expr\ClosureUse[parseVar($2), $1]; }
;

function_call:
      name argument_list { $$ = Expr\FuncCall[$1, $2]; }
    | class_name_or_var T_PAAMAYIM_NEKUDOTAYIM T_STRING argument_list { $$ = Expr\StaticCall[$1, $3, $4]; }
    | class_name_or_var T_PAAMAYIM_NEKUDOTAYIM '{' expr '}' argument_list { $$ = Expr\StaticCall[$1, $4, $6]; }
    | static_property argument_list {
            if ($1 instanceof Node\Expr\StaticPropertyFetch) {
                $$ = Expr\StaticCall[$1->class, Expr\Variable[$1->name], $2];
            } elseif ($1 instanceof Node\Expr\ArrayDimFetch) {
                $tmp = $1;
                while ($tmp->var instanceof Node\Expr\ArrayDimFetch) {
                    $tmp = $tmp->var;
                }

                $$ = Expr\StaticCall[$tmp->var->class, $1, $2];
                $tmp->var = Expr\Variable[$tmp->var->name];
            } else {
                throw new \Exception;
            }
          }
    | variable_without_objects argument_list { $$ = Expr\FuncCall[$1, $2]; }
    | function_call '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; } /* alternative array syntax missing intentionally */
;

class_name:
      T_STATIC { $$ = Name[$1]; }
    | name { $$ = $1; }
;

name:
      namespace_name_parts { $$ = Name[$1]; }
    | T_NS_SEPARATOR namespace_name_parts { $$ = Name\FullyQualified[$2]; }
    | T_NAMESPACE T_NS_SEPARATOR namespace_name_parts { $$ = Name\Relative[$3]; }
;

class_name_reference:
      class_name { $$ = $1; }
    | dynamic_class_name_reference { $$ = $1; }
;

dynamic_class_name_reference:
      object_access_for_dcnr { $$ = $1; }
    | base_variable { $$ = $1; }
;

class_name_or_var:
      class_name { $$ = $1; }
    | reference_variable { $$ = $1; }
;

object_access_for_dcnr:
      base_variable T_OBJECT_OPERATOR object_property { $$ = Expr\PropertyFetch[$1, $3]; }
    | object_access_for_dcnr T_OBJECT_OPERATOR object_property { $$ = Expr\PropertyFetch[$1, $3]; }
    | object_access_for_dcnr '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | object_access_for_dcnr '{' expr '}' { $$ = Expr\ArrayDimFetch[$1, $3]; }
;

exit_expr:
      /* empty */ { $$ = null; }
    | '(' ')' { $$ = null; }
    | parentheses_expr { $$ = $1; }
;

backticks_expr:
      /* empty */ { $$ = array(); }
    | T_ENCAPSED_AND_WHITESPACE { $$ = array(Scalar\String_::parseEscapeSequences($1, '`')); }
    | encaps_list { parseEncapsed($1, '`'); $$ = $1; }
;

ctor_arguments:
      /* empty */ { $$ = array(); }
    | argument_list { $$ = $1; }
;

common_scalar:
      T_LNUMBER { $$ = Scalar\LNumber[Scalar\LNumber::parse($1)]; }
    | T_DNUMBER { $$ = Scalar\DNumber[Scalar\DNumber::parse($1)]; }
    | T_CONSTANT_ENCAPSED_STRING { $$ = Scalar\String_[Scalar\String_::parse($1)]; }
    | T_LINE { $$ = Scalar\MagicConst\Line[]; }
    | T_FILE { $$ = Scalar\MagicConst\File[]; }
    | T_DIR { $$ = Scalar\MagicConst\Dir[]; }
    | T_CLASS_C { $$ = Scalar\MagicConst\Class_[]; }
    | T_TRAIT_C { $$ = Scalar\MagicConst\Trait_[]; }
    | T_METHOD_C { $$ = Scalar\MagicConst\Method[]; }
    | T_FUNC_C { $$ = Scalar\MagicConst\Function_[]; }
    | T_NS_C { $$ = Scalar\MagicConst\Namespace_[]; }
    | T_START_HEREDOC T_ENCAPSED_AND_WHITESPACE T_END_HEREDOC { $$ = Scalar\String_[Scalar\String_::parseDocString($1, $2)]; }
    | T_START_HEREDOC T_END_HEREDOC { $$ = Scalar\String_['']; }
;

static_scalar:
      common_scalar { $$ = $1; }
    | class_name T_PAAMAYIM_NEKUDOTAYIM class_const_name { $$ = Expr\ClassConstFetch[$1, $3]; }
    | name { $$ = Expr\ConstFetch[$1]; }
    | T_ARRAY '(' static_array_pair_list ')' { $$ = Expr\Array_[$3]; }
    | '[' static_array_pair_list ']' { $$ = Expr\Array_[$2]; }
    | static_operation { $$ = $1; }
;

static_operation:
      static_scalar T_BOOLEAN_OR static_scalar { $$ = Expr\BinaryOp\BooleanOr [$1, $3]; }
    | static_scalar T_BOOLEAN_AND static_scalar { $$ = Expr\BinaryOp\BooleanAnd[$1, $3]; }
    | static_scalar T_LOGICAL_OR static_scalar { $$ = Expr\BinaryOp\LogicalOr [$1, $3]; }
    | static_scalar T_LOGICAL_AND static_scalar { $$ = Expr\BinaryOp\LogicalAnd[$1, $3]; }
    | static_scalar T_LOGICAL_XOR static_scalar { $$ = Expr\BinaryOp\LogicalXor[$1, $3]; }
    | static_scalar '|' static_scalar { $$ = Expr\BinaryOp\BitwiseOr [$1, $3]; }
    | static_scalar '&' static_scalar { $$ = Expr\BinaryOp\BitwiseAnd[$1, $3]; }
    | static_scalar '^' static_scalar { $$ = Expr\BinaryOp\BitwiseXor[$1, $3]; }
    | static_scalar '.' static_scalar { $$ = Expr\BinaryOp\Concat    [$1, $3]; }
    | static_scalar '+' static_scalar { $$ = Expr\BinaryOp\Plus      [$1, $3]; }
    | static_scalar '-' static_scalar { $$ = Expr\BinaryOp\Minus     [$1, $3]; }
    | static_scalar '*' static_scalar { $$ = Expr\BinaryOp\Mul       [$1, $3]; }
    | static_scalar '/' static_scalar { $$ = Expr\BinaryOp\Div       [$1, $3]; }
    | static_scalar '%' static_scalar { $$ = Expr\BinaryOp\Mod       [$1, $3]; }
    | static_scalar T_SL static_scalar { $$ = Expr\BinaryOp\ShiftLeft [$1, $3]; }
    | static_scalar T_SR static_scalar { $$ = Expr\BinaryOp\ShiftRight[$1, $3]; }
    | static_scalar T_POW static_scalar { $$ = Expr\BinaryOp\Pow       [$1, $3]; }
    | '+' static_scalar %prec T_INC { $$ = Expr\UnaryPlus [$2]; }
    | '-' static_scalar %prec T_INC { $$ = Expr\UnaryMinus[$2]; }
    | '!' static_scalar { $$ = Expr\BooleanNot[$2]; }
    | '~' static_scalar { $$ = Expr\BitwiseNot[$2]; }
    | static_scalar T_IS_IDENTICAL static_scalar { $$ = Expr\BinaryOp\Identical     [$1, $3]; }
    | static_scalar T_IS_NOT_IDENTICAL static_scalar { $$ = Expr\BinaryOp\NotIdentical  [$1, $3]; }
    | static_scalar T_IS_EQUAL static_scalar { $$ = Expr\BinaryOp\Equal         [$1, $3]; }
    | static_scalar T_IS_NOT_EQUAL static_scalar { $$ = Expr\BinaryOp\NotEqual      [$1, $3]; }
    | static_scalar '<' static_scalar { $$ = Expr\BinaryOp\Smaller       [$1, $3]; }
    | static_scalar T_IS_SMALLER_OR_EQUAL static_scalar { $$ = Expr\BinaryOp\SmallerOrEqual[$1, $3]; }
    | static_scalar '>' static_scalar { $$ = Expr\BinaryOp\Greater       [$1, $3]; }
    | static_scalar T_IS_GREATER_OR_EQUAL static_scalar { $$ = Expr\BinaryOp\GreaterOrEqual[$1, $3]; }
    | static_scalar '?' static_scalar ':' static_scalar { $$ = Expr\Ternary[$1, $3,   $5]; }
    | static_scalar '?' ':' static_scalar { $$ = Expr\Ternary[$1, null, $4]; }
    | static_scalar '[' static_scalar ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | '(' static_scalar ')' { $$ = $2; }
;

constant:
      name { $$ = Expr\ConstFetch[$1]; }
    | class_name_or_var T_PAAMAYIM_NEKUDOTAYIM class_const_name { $$ = Expr\ClassConstFetch[$1, $3]; }
;

scalar:
      common_scalar { $$ = $1; }
    | constant { $$ = $1; }
    | '"' encaps_list '"' { parseEncapsed($2, '"'); $$ = Scalar\Encapsed[$2]; }
    | T_START_HEREDOC encaps_list T_END_HEREDOC { parseEncapsedDoc($2); $$ = Scalar\Encapsed[$2]; }
;

class_const_name:
      T_STRING { $$ = $1; }
    | T_CLASS { $$ = 'class'; }
;

static_array_pair_list:
      /* empty */ { $$ = array(); }
    | non_empty_static_array_pair_list optional_comma { $$ = $1; }
;

optional_comma:
      /* empty */
    | ','
;

non_empty_static_array_pair_list:
      non_empty_static_array_pair_list ',' static_array_pair { push($1, $3); }
    | static_array_pair { init($1); }
;

static_array_pair:
      static_scalar T_DOUBLE_ARROW static_scalar { $$ = Expr\ArrayItem[$3, $1,   false]; }
    | static_scalar { $$ = Expr\ArrayItem[$1, null, false]; }
;

variable:
      object_access { $$ = $1; }
    | base_variable { $$ = $1; }
    | function_call { $$ = $1; }
    | new_expr_array_deref { $$ = $1; }
;

new_expr_array_deref:
      '(' new_expr ')' '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$2, $5]; }
    | new_expr_array_deref '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; } /* alternative array syntax missing intentionally */
;

object_access:
      variable_or_new_expr T_OBJECT_OPERATOR object_property { $$ = Expr\PropertyFetch[$1, $3]; }
    | variable_or_new_expr T_OBJECT_OPERATOR object_property argument_list { $$ = Expr\MethodCall[$1, $3, $4]; }
    | object_access argument_list { $$ = Expr\FuncCall[$1, $2]; }
    | object_access '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | object_access '{' expr '}' { $$ = Expr\ArrayDimFetch[$1, $3]; }
;

variable_or_new_expr:
      variable { $$ = $1; }
    | '(' new_expr ')' { $$ = $2; }
;

variable_without_objects:
      reference_variable { $$ = $1; }
    | '$' variable_without_objects { $$ = Expr\Variable[$2]; }
;

base_variable:
      variable_without_objects { $$ = $1; }
    | static_property { $$ = $1; }
;

static_property:
      class_name_or_var T_PAAMAYIM_NEKUDOTAYIM '$' reference_variable { $$ = Expr\StaticPropertyFetch[$1, $4]; }
    | static_property_with_arrays { $$ = $1; }
;

static_property_with_arrays:
      class_name_or_var T_PAAMAYIM_NEKUDOTAYIM T_VARIABLE { $$ = Expr\StaticPropertyFetch[$1, parseVar($3)]; }
    | class_name_or_var T_PAAMAYIM_NEKUDOTAYIM '$' '{' expr '}' { $$ = Expr\StaticPropertyFetch[$1, $5]; }
    | static_property_with_arrays '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | static_property_with_arrays '{' expr '}' { $$ = Expr\ArrayDimFetch[$1, $3]; }
;

reference_variable:
      reference_variable '[' dim_offset ']' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | reference_variable '{' expr '}' { $$ = Expr\ArrayDimFetch[$1, $3]; }
    | T_VARIABLE { $$ = Expr\Variable[parseVar($1)]; }
    | '$' '{' expr '}' { $$ = Expr\Variable[$3]; }
;

dim_offset:
      /* empty */ { $$ = null; }
    | expr { $$ = $1; }
;

object_property:
      T_STRING { $$ = $1; }
    | '{' expr '}' { $$ = $2; }
    | variable_without_objects { $$ = $1; }
;

list_expr:
      T_LIST '(' list_expr_elements ')' { $$ = Expr\List_[$3]; }
;

list_expr_elements:
      list_expr_elements ',' list_expr_element { push($1, $3); }
    | list_expr_element { init($1); }
;

list_expr_element:
      variable { $$ = $1; }
    | list_expr { $$ = $1; }
    | /* empty */ { $$ = null; }
;

array_pair_list:
      /* empty */ { $$ = array(); }
    | non_empty_array_pair_list optional_comma { $$ = $1; }
;

non_empty_array_pair_list:
      non_empty_array_pair_list ',' array_pair { push($1, $3); }
    | array_pair { init($1); }
;

array_pair:
      expr T_DOUBLE_ARROW expr { $$ = Expr\ArrayItem[$3, $1,   false]; }
    | expr { $$ = Expr\ArrayItem[$1, null, false]; }
    | expr T_DOUBLE_ARROW '&' variable { $$ = Expr\ArrayItem[$4, $1,   true]; }
    | '&' variable { $$ = Expr\ArrayItem[$2, null, true]; }
;

encaps_list:
      encaps_list encaps_var { push($1, $2); }
    | encaps_list T_ENCAPSED_AND_WHITESPACE { push($1, $2); }
    | encaps_var { init($1); }
    | T_ENCAPSED_AND_WHITESPACE encaps_var { init($1, $2); }
;

encaps_var:
      T_VARIABLE { $$ = Expr\Variable[parseVar($1)]; }
    | T_VARIABLE '[' encaps_var_offset ']' { $$ = Expr\ArrayDimFetch[Expr\Variable[parseVar($1)], $3]; }
    | T_VARIABLE T_OBJECT_OPERATOR T_STRING { $$ = Expr\PropertyFetch[Expr\Variable[parseVar($1)], $3]; }
    | T_DOLLAR_OPEN_CURLY_BRACES expr '}' { $$ = Expr\Variable[$2]; }
    | T_DOLLAR_OPEN_CURLY_BRACES T_STRING_VARNAME '}' { $$ = Expr\Variable[$2]; }
    | T_DOLLAR_OPEN_CURLY_BRACES T_STRING_VARNAME '[' expr ']' '}' { $$ = Expr\ArrayDimFetch[Expr\Variable[$2], $4]; }
    | T_CURLY_OPEN variable '}' { $$ = $2; }
;

encaps_var_offset:
      T_STRING { $$ = Scalar\String_[$1]; }
    | T_NUM_STRING { $$ = Scalar\String_[$1]; }
    | T_VARIABLE { $$ = Expr\Variable[parseVar($1)]; }
;