我发现两种用法都可以require('functions.php')和require 'functions.php'，那么它在php中到底是语法还是函数呢？我们能否在自己写php插件时也实现这样的用法？也就是可以这样用my_custom 'parms'。
解决方案
语法
Zend/zend_language_scanner.l
<ST_IN_SCRIPTING>"eval" { return T_EVAL;}<ST_IN_SCRIPTING>"include" { return T_INCLUDE;}<ST_IN_SCRIPTING>"include_once" { return T_INCLUDE_ONCE;}<ST_IN_SCRIPTING>"require" { return T_REQUIRE;}<ST_IN_SCRIPTING>"require_once" { return T_REQUIRE_ONCE;}Zend/zend_language_parser.y
internal_functions_in_yacc: T_ISSET '(' isset_variables ')' { $$ = $3; } | T_EMPTY '(' variable ')' { zend_do_isset_or_isempty(ZEND_ISEMPTY, &$$, &$3 TSRMLS_CC); } | T_INCLUDE expr { zend_do_include_or_eval(ZEND_INCLUDE, &$$, &$2 TSRMLS_CC); } | T_INCLUDE_ONCE expr { zend_do_include_or_eval(ZEND_INCLUDE_ONCE, &$$, &$2 TSRMLS_CC); } | T_EVAL '(' expr ')' { zend_do_include_or_eval(ZEND_EVAL, &$$, &$3 TSRMLS_CC); } | T_REQUIRE expr { zend_do_include_or_eval(ZEND_REQUIRE, &$$, &$2 TSRMLS_CC); } | T_REQUIRE_ONCE expr { zend_do_include_or_eval(ZEND_REQUIRE_ONCE, &$$, &$2 TSRMLS_CC); };Zend/zend_compile.c
void zend_do_include_or_eval(int type, znode *result, const znode *op1 TSRMLS_DC) { zend_do_extended_fcall_begin(TSRMLS_C); { zend_op *opline = get_next_op(CG(active_op_array) TSRMLS_CC); opline->opcode = ZEND_INCLUDE_OR_EVAL; opline->result_type = IS_VAR; opline->result.var = get_temporary_variable(CG(active_op_array)); SET_NODE(opline->op1, op1); SET_UNUSED(opline->op2); opline->extended_value = type; GET_NODE(result, opline->result); } zend_do_extended_fcall_end(TSRMLS_C);}