本项目实现了一个类似Django的模板引擎，语法类似。用于生成代码。实现了变量，For，IF这三个功能。
{{%VarName%}}
用{{%%}}括起来的代表变量,模板引擎会根据传进来的数据来替换这个变量
{% for it in xlist %}
{{%it%}}
{% endfor %}
循环我只实现了for,不过我觉的应该足够了。需要{%for python语句%}{% endfor %}括起来。模板引擎会将循环输出括起来的内容。for循环里面可以嵌套for循环。
{% if 条件 %}
内容
{% endif %}
模板引擎会根据条件是否满足来决定是否显示里面的内容。
from CodeTemplate import Template
code = '''
struct {{%Name%}}
{
{% for it in Rules %}
{{%it['Type']%}} {{%it['Name']%}};
{% endfor %}
vector<string> Other;
static ARGS FromStringList(int argc, char *argv[])
{
ARGS ret ;
{% for it in Rules %}
{% if it['IsPrefix']==0 and it['Type'] == 'bool' %}
ret.{{%it['Name']%}} = false;
{% endif %}
{% endfor %}
int i=0;
while(++i<argc)
{
string current = argv[i];
{% for it in Rules %}
{% if it['IsPrefix']==1 and it['Type'] == 'string' %}
if(current.compare("{{%it['ArgName']%}}") == 0){
if(++i>=argc) throw exception("After {{%it['ArgName']%}} Is Nothing");
ret.{{%it['Name']%}} = argv[i];
continue;
}
{% endif %}
{% endfor %}
{% for it in Rules %}
{% if it['IsPrefix']==0 and it['Type'] == 'bool' %}
if(current.compare("{{%it['ArgName']%}}") == 0 ){
ret.{{%it['Name']%}} = true;
continue;
}
{% endif %}
{% endfor %}
{% for it in Rules %}
{% if it['ArgName']=="" %}
if(ret.{{%it['Name']%}}.empty())
{
ret.{{%it['Name']%}} = current;
continue;
}
{% endif %}
{% endfor %}
ret.Other.push_back(current);
}
return ret;
}
};
'''
#<RULE IsPrefix="0" ArgName="" Name="FileName" Type="string"/>
codecontext = {
'Name':'ARGS',
'Rules':[
{'IsPrefix':0,'ArgName':'','Name':"FileName",'Type':'string'},
{'IsPrefix':1,'ArgName':'-x','Name':"XMLFileName",'Type':'string'},
{'IsPrefix':1,'ArgName':'-cs','Name':"CSFileName",'Type':'string'},
{'IsPrefix':0,'ArgName':'-c','Name':"CFlag",'Type':'bool'},
{'IsPrefix':0,'ArgName':'-b','Name':"BFlag",'Type':'bool'},
]
}
print(Template(code)(codecontext))运行该程序将会生成一下C++代码
struct ARGS
{
string FileName;
string XMLFileName;
string CSFileName;
bool CFlag;
bool BFlag;
vector<string> Other;
static ARGS FromStringList(int argc, char *argv[])
{
ARGS ret ;
ret.CFlag = false;
ret.BFlag = false;
int i=0;
while(++i<argc)
{
string current = argv[i];
if(current.compare("-x") == 0){
if(++i>=argc) throw exception("After -x Is Nothing");
ret.XMLFileName = argv[i];
continue;
}
if(current.compare("-cs") == 0){
if(++i>=argc) throw exception("After -cs Is Nothing");
ret.CSFileName = argv[i];
continue;
}
if(current.compare("-c") == 0 ){
ret.CFlag = true;
continue;
}
if(current.compare("-b") == 0 ){
ret.BFlag = true;
continue;
}
if(ret.FileName.empty())
{
ret.FileName = current;
continue;
}
ret.Other.push_back(current);
}
return ret;
}
};本例是为了测试变量，for循环以及if语句。其实如果使用python的高阶函数可以去掉本例的所有if块。如下:
from CodeTemplate import Template
code = '''
struct {{%Name%}}
{
{% for it in Rules %}
{{%it['Type']%}} {{%it['Name']%}};
{% endfor %}
vector<string> Other;
static ARGS FromStringList(int argc, char *argv[])
{
ARGS ret ;
{% for it in filter(lambda it:it['IsPrefix']==0 and it['Type'] == 'bool',Rules) %}
ret.{{%it['Name']%}} = false;
{% endfor %}
int i=0;
while(++i<argc)
{
string current = argv[i];
{% for it in filter(lambda it:it['IsPrefix']==1 and it['Type'] == 'string',Rules) %}
if(current.compare("{{%it['ArgName']%}}") == 0){
if(++i>=argc) throw exception("After {{%it['ArgName']%}} Is Nothing");
ret.{{%it['Name']%}} = argv[i];
continue;
}
{% endfor %}
{% for it in filter(lambda it: it['IsPrefix']==0 and it['Type'] == 'bool',Rules) %}
if(current.compare("{{%it['ArgName']%}}") == 0 ){
ret.{{%it['Name']%}} = true;
continue;
}
{% endfor %}
{% for it in filter(lambda it:it['ArgName']=="",Rules) %}
if(ret.{{%it['Name']%}}.empty())
{
ret.{{%it['Name']%}} = current;
continue;
}
{% endfor %}
ret.Other.push_back(current);
}
return ret;
}
};
'''
#<RULE IsPrefix="0" ArgName="" Name="FileName" Type="string"/>
codecontext = {
'Name':'ARGS',
'Rules':[
{'IsPrefix':0,'ArgName':'','Name':"FileName",'Type':'string'},
{'IsPrefix':1,'ArgName':'-x','Name':"XMLFileName",'Type':'string'},
{'IsPrefix':1,'ArgName':'-cs','Name':"CSFileName",'Type':'string'},
{'IsPrefix':0,'ArgName':'-c','Name':"CFlag",'Type':'bool'},
{'IsPrefix':0,'ArgName':'-b','Name':"BFlag",'Type':'bool'},
]
}
print(Template(code)(codecontext))改成这样的话会简洁很多。当然输出的内容是不变的。
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