From Zend/zend_language_parser.y:
%left T_INCLUDE T_INCLUDE_ONCE T_EVAL T_REQUIRE T_REQUIRE_ONCE
%left ','
%left T_LOGICAL_OR
%left T_LOGICAL_XOR
%left T_LOGICAL_AND
%right T_PRINT
%left '=' T_PLUS_EQUAL T_MINUS_EQUAL T_MUL_EQUAL T_DIV_EQUAL T_CONCAT_EQUAL
T_MOD_EQUAL T_AND_EQUAL T_OR_EQUAL T_XOR_EQUAL T_SL_EQUAL T_SR_EQUAL
%left '?' ':'
%left T_BOOLEAN_OR
%left T_BOOLEAN_AND
%left '|'
%left '^'
%left '&'
%nonassoc T_IS_EQUAL T_IS_NOT_EQUAL T_IS_IDENTICAL T_IS_NOT_IDENTICAL
%nonassoc '<' T_IS_SMALLER_OR_EQUAL '>' T_IS_GREATER_OR_EQUAL
%left T_SL T_SR
%left '+' '-' '.'
%left '*' '/' '%'
%right '!' '~' T_INC T_DEC T_INT_CAST T_DOUBLE_CAST T_STRING_CAST T_ARRAY_CAST
T_OBJECT_CAST T_BOOL_CAST T_UNSET_CAST '@'
%right '['
%nonassoc T_NEW T_INSTANCEOF
%token T_EXIT
%token T_IF
%left T_ELSEIF
%left T_ELSE
%left T_ENDIF
%token T_LNUMBER
%token T_DNUMBER
%token T_STRING
%token T_STRING_VARNAME
%token T_VARIABLE
%token T_NUM_STRING
%token T_INLINE_HTML
%token T_CHARACTER
%token T_BAD_CHARACTER
%token T_ENCAPSED_AND_WHITESPACE
%token T_CONSTANT_ENCAPSED_STRING
%token T_ECHO
%token T_DO
%token T_WHILE
%token T_ENDWHILE
%token T_FOR
%token T_ENDFOR
%token T_FOREACH
%token T_ENDFOREACH
%token T_DECLARE
%token T_ENDDECLARE
%token T_INSTANCEOF
%token T_AS
%token T_SWITCH
%token T_ENDSWITCH
%token T_CASE
%token T_DEFAULT
%token T_BREAK
%token T_CONTINUE
%token T_FUNCTION
%token T_CONST
%token T_RETURN
%token T_TRY
%token T_CATCH
%token T_THROW
%token T_USE
%token T_GLOBAL
%right T_STATIC T_ABSTRACT T_FINAL T_PRIVATE T_PROTECTED T_PUBLIC
%token T_VAR
%token T_UNSET
%token T_ISSET
%token T_EMPTY
%token T_CLASS
%token T_INTERFACE
%token T_EXTENDS
%token T_IMPLEMENTS
%token T_OBJECT_OPERATOR
%token T_DOUBLE_ARROW
%token T_LIST
%token T_ARRAY
%token T_CLASS_C
%token T_FUNC_C
%token T_LINE
%token T_FILE
%token T_COMMENT
%token T_DOC_COMMENT
%token T_OPEN_TAG
%token T_OPEN_TAG_WITH_ECHO
%token T_CLOSE_TAG
%token T_WHITESPACE
%token T_START_HEREDOC
%token T_END_HEREDOC
%token T_DOLLAR_OPEN_CURLY_BRACES
%token T_CURLY_OPEN
%token T_PAAMAYIM_NEKUDOTAYIM
}