GScript 编写标准库示例详解

    string fileName = d.unix("Asia/Shanghai") + "temp.gs" ;
    s.writeFile(fileName, body, 438);
    string pwd = s.getwd();
    // string res = s.command("gscript", fileName);
    string res = s.command("docker","run","--rm","-v", pwd+":/usr/src/gscript","-w","/usr/src/gscript", "crossoverjie/gscript","gscript", fileName);
    s.remove(fileName);
    r.body = res;
    r.ast = dumpAST(body);
    r.symbol=dumpSymbol(body);
    ctx.JSON(200, r);

docker pull crossoverjie/gscript
docker run --rm -it  crossoverjie/gscript:latest gscript

docker run --rm -v $PWD:/usr/src/gscript -w /usr/src/gscript crossoverjie/gscript gscript {yourpath}/temp.gs

// 字符串工具类
StringBuilder b = StringBuilder();
b.writeString("10");
b.writeString("20");
int l = b.writeString("30");
string s = b.String();
printf("s:%s, len=%d ",s,l);
assertEqual(s,"102030");
byte[] b2 = toByteArray("40");
b.WriteBytes(b2);
s = b.String();
assertEqual(s,"10203040");
println(s);
// Strings 工具类
Strings s = Strings();
string[] elems = {"name=xxx","age=xx"};
string ret = s.join(elems, "&");
println(ret);
assertEqual(ret, "name=xxx&age=xx");
bool b = s.hasPrefix("http://www.xx.com", "http");
println(b);
assertEqual(b,true);
b = s.hasPrefix("http://www.xx.com", "https");
println(b);
assertEqual(b,false);

class StringBuilder{
    byte[] buf = [0]{};
    // append contents to buf, it returns the length of s
    int writeString(string s){
        byte[] temp = toByteArray(s);
        append(buf, temp);
        return len(temp);
    }
    // append b to buf, it returns the length of b.
    int WriteBytes(byte[] b){
        append(buf, b);
        return len(b);
    }
    // copies the buffer to a new.
    grow(int n){
        if (n > 0) {
            // when there is not enough space left.
            if (cap(buf) - len(buf) < n) {
                byte[] newBuf = [len(buf), 2*cap(buf)+n]{};
                copy(newBuf, buf);
                buf = newBuf;
            }
        }   
    }
    string String(){
        return toString(buf);
    }
}

class Strings{
    // concatenates the elements of its first argument to create a single string. The separator
    // string sep is placed between elements in the resulting string.
    string join(string[] elems, string sep){
        if (len(elems) == 0) {
            return "";
        }
        if (len(elems) == 1) {
            return elems[0];
        }
        byte[] bs = toByteArray(sep);
        int n = len(bs) * (len(elems) -1);
        for (int i=0; i < len(elems); i++) {
            string s = elems[i];
            byte[] bs = toByteArray(s);
            n = n + len(bs);
        }
        StringBuilder sb = StringBuilder();
        sb.grow(n);
        string first = elems[0];
        sb.writeString(first);
        string[] remain = elems[1:len(elems)];
        for(int i=0; i < len(remain); i++){
            sb.writeString(sep);
            string r = remain[i];
            sb.writeString(r);
        }
        return sb.String();
    }
    // tests whether the string s begins with prefix.
    bool hasPrefix(string s, string prefix){
        byte[] bs = toByteArray(s);
        byte[] bp = toByteArray(prefix);    
        return len(bs) >= len(bp) && toString(bs[0:len(bp)]) == prefix;
    }
}