Merge branch 'master' into tetris

merge array stuff into tetris

5 files changed, 267 insertions, 77 deletions

diff --git a/arrays.prn b/arrays.prn
new file mode 100644
index 0000000..2dc7d43
--- /dev/null
+++ b/arrays.prn
@@ -0,0 +1,13 @@
+mkarray
+1 "i" store
+i 11 < while
+	i +
+	i 1 + "i" store
+i 11 < end
+stackdump
+0 "i" store
+i 10 < while
+	"Array index " i + ": " + print
+	i arridx print lf
+	i 1 + "i" store
+i 10 < end
diff --git a/functions.cpp b/functions.cpp
index 7a6ce36..261405e 100644
--- a/functions.cpp
+++ b/functions.cpp
@@ -7,6 +7,7 @@
 #include <string>
 #include <functional>
 #include <cmath>
+#include <cassert>
 #include <unistd.h>
 #include <fcntl.h>
 
@@ -30,81 +31,107 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("+",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(!a.isstr&&!b.isstr){
+		if(a.type==SIT_INT&&b.type==SIT_INT){
 			S.emplace_back(a.intval+b.intval);
 			return;
 		}
-		if(!a.isstr){
-			a.strval=to_string(a.intval);
-			a.isstr=true;
+		if(a.type==SIT_ARR||b.type==SIT_ARR){
+			if(a.type!=SIT_ARR){
+				b.arrval.insert(b.arrval.begin(),move(a));
+				S.push_back(move(b));
+			} else if(b.type!=SIT_ARR){
+				a.arrval.push_back(move(b));
+				S.push_back(move(a));
+			} else {
+				const auto bsz=b.arrval.size();
+				a.arrval.reserve(a.arrval.size()+b.arrval.size());
+				for(unsigned int i=0;i<bsz;i++)a.arrval.push_back(move(b.arrval[i]));
+				S.push_back(move(a));
+			}
+			return;
 		}
-		if(!b.isstr){
-			b.strval=to_string(b.intval);
-			b.isstr=true;
+		//none is array, and one is not int -> at least one is string and other is int
+		if(a.type!=SIT_STR){
+			S.emplace_back(to_string(a.intval)+b.strval);
+		} else if(b.type!=SIT_STR){
+			S.emplace_back(a.strval+to_string(b.intval));
+		} else {
+			S.emplace_back(a.strval+b.strval);
 		}
-		S.emplace_back(a.strval+b.strval);
 	}},
 	{"-",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("-",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '-' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '-' expects two number arguments");
 		S.emplace_back(a.intval-b.intval);
 	}},
 	{"*",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("*",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '*' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '*' expects two number arguments");
 		S.emplace_back(a.intval*b.intval);
 	}},
 	{"/",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("/",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '/' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '/' expects two number arguments");
 		S.emplace_back(a.intval/b.intval);
 	}},
 	{"%",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("%",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '%' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '%' expects two number arguments");
 		S.emplace_back(a.intval%b.intval);
 	}},
 	{"&",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("&",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '&' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '&' expects two number arguments");
 		S.emplace_back(a.intval&b.intval);
 	}},
 	{"|",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("|",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '|' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '|' expects two number arguments");
 		S.emplace_back(a.intval|b.intval);
 	}},
 	{"~",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("~",1)
 		Stackitem &back=S.back();
-		if(back.isstr)throw string("Builtin '~' cannot accept a string argument");
+		if(back.type!=SIT_INT)throw string("Builtin '~' expects a number argument");
 		else back.intval=~back.intval;
 	}},
 	{"^",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("^",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr||b.isstr)throw string("Builtin '^' cannot accept a string argument");
+		if(a.type!=SIT_INT||b.type!=SIT_INT)
+			throw string("Builtin '^' expects two number arguments");
 		S.emplace_back((int)pow(a.intval,b.intval));
 	}},
 	{"!",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("!",1)
 		Stackitem &back=S.back();
-		if(back.isstr){
-			back.isstr=false;
+		if(back.type==SIT_ARR){
+			back.type=SIT_INT;
+			back.intval=!back.arrval.size();
+			back.arrval.clear();
+		} else if(back.type==SIT_STR){
+			back.type=SIT_INT;
 			back.intval=!back.strval.size();
+			back.strval.clear();
 		} else back.intval=!back.intval;
 	}},
 	{"=",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
@@ -117,25 +144,30 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("<",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr&&b.isstr)S.emplace_back(a.strval<b.strval);
-		else if(!a.isstr&&!b.isstr)S.emplace_back(a.intval<b.intval);
-		else if(a.isstr)S.emplace_back(a.strval<to_string(b.intval));
+		if(a.type==SIT_ARR&&b.type==SIT_ARR)S.emplace_back(a.arrval.size()<b.arrval.size());
+		else if(a.type==SIT_ARR||b.type==SIT_ARR){
+			throw string("Builtin '<' cannot accept an array and a non-array argument");
+		} else if(a.type==SIT_STR&&b.type==SIT_STR)S.emplace_back(a.strval<b.strval);
+		else if(a.type==SIT_INT&&b.type==SIT_INT)S.emplace_back(a.intval<b.intval);
+		else if(a.type==SIT_STR)S.emplace_back(a.strval<to_string(b.intval));
 		else S.emplace_back(to_string(a.intval)<b.strval);
 	}},
 	{">",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE(">",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		if(a.isstr&&b.isstr)S.emplace_back(a.strval>b.strval);
-		else if(!a.isstr&&!b.isstr)S.emplace_back(a.intval>b.intval);
-		else if(a.isstr)S.emplace_back(a.strval>to_string(b.intval));
+		if(a.type==SIT_ARR&&b.type==SIT_ARR)S.emplace_back(a.arrval.size()>b.arrval.size());
+		else if(a.type==SIT_ARR||b.type==SIT_ARR){
+			throw string("Builtin '>' cannot accept an array and a non-array argument");
+		} else if(a.type==SIT_STR&&b.type==SIT_STR)S.emplace_back(a.strval>b.strval);
+		else if(a.type==SIT_INT&&b.type==SIT_INT)S.emplace_back(a.intval>b.intval);
+		else if(a.type==SIT_STR)S.emplace_back(a.strval>to_string(b.intval));
 		else S.emplace_back(to_string(a.intval)>b.strval);
 	}},
 	{"print",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("print",1)
-		Stackitem v=move(S.back()); S.pop_back();
-		if(v.isstr)cout<<v.strval<<flush;
-		else cout<<v.intval<<flush;
+		cout<<to_string(S.back())<<flush;
+		S.pop_back();
 	}},
 	{"lf",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("lf",0)
@@ -146,7 +178,7 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		string line;
 		getline(cin,line);
 		if(!cin)S.emplace_back(-1);
-		else S.emplace_back(line);
+		else S.emplace_back(move(line));
 	}},
 	{"getc",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("getc",0)
@@ -158,23 +190,23 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("fprint",2)
 		Stackitem file=move(S.back()); S.pop_back();
 		Stackitem v=move(S.back()); S.pop_back();
-		if(file.isstr)throw string("Second argument to 'fprint' not a number");
-		if(v.isstr)write(file.intval,v.strval.data(),v.strval.size());
+		if(file.type!=SIT_INT)throw string("Second argument to 'fprint' not a number");
+		if(v.type==SIT_STR)write(file.intval,v.strval.data(),v.strval.size());
 		else {
-			string s=to_string(v.intval);
+			string s=to_string(v);
 			write(file.intval,s.data(),s.size());
 		}
 	}},
 	{"flf",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("flf",1)
 		Stackitem file=move(S.back()); S.pop_back();
-		if(file.isstr)throw string("Argument to 'flf' not a number");
+		if(file.type!=SIT_INT)throw string("Argument to 'flf' not a number");
 		write(file.intval,"\n",1);
 	}},
 	{"fgetc",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("fgetc",1)
 		Stackitem file=move(S.back()); S.pop_back();
-		if(file.isstr)throw string("Argument to 'fgetc' not a number");
+		if(file.type!=SIT_INT)throw string("Argument to 'fgetc' not a number");
 		char c;
 		int ret=read(file.intval,&c,1);
 		if(ret==-1)perror("read");
@@ -185,8 +217,8 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("fopen",2)
 		Stackitem mode=move(S.back()); S.pop_back();
 		Stackitem fname=move(S.back()); S.pop_back();
-		if(!fname.isstr)throw string("First argument to 'fopen' not a string");
-		if(!mode.isstr)throw string("Second argument to 'fopen' not a string");
+		if(fname.type!=SIT_STR)throw string("First argument to 'fopen' not a string");
+		if(mode.type!=SIT_STR)throw string("Second argument to 'fopen' not a string");
 		int oflag=0;
 		if(mode.strval.find('r')!=string::npos)oflag|=O_RDONLY;
 		if(mode.strval.find('w')!=string::npos){
@@ -207,7 +239,7 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 	{"argvget",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("argvget",1)
 		Stackitem idx=move(S.back()); S.pop_back();
-		if(idx.isstr)throw string("Argument to 'argvget' not a number");
+		if(idx.type!=SIT_INT)throw string("Argument to 'argvget' not a number");
 		if(idx.intval<0||idx.intval>=g_argc)throw string("Argument to 'argvget' out of bounds");
 		S.emplace_back(g_argv[idx.intval]);
 	}},
@@ -223,13 +255,13 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("swap",2)
 		Stackitem b=move(S.back()); S.pop_back();
 		Stackitem a=move(S.back()); S.pop_back();
-		S.push_back(b);
-		S.push_back(a);
+		S.push_back(move(b));
+		S.push_back(move(a));
 	}},
 	{"store",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("store",2)
 		Stackitem name=move(S.back()); S.pop_back();
-		if(!name.isstr)throw string("Second argument to 'store' not a string");
+		if(name.type!=SIT_STR)throw string("Second argument to 'store' not a string");
 		auto it=variables.find(name.strval);
 		bool exists=it!=variables.end();
 		if(scopestack.size()&&scopestack.top().find(name.strval)==scopestack.top().end()){
@@ -247,23 +279,31 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 	{"gstore",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("gstore",2)
 		Stackitem name=move(S.back()); S.pop_back();
-		if(!name.isstr)throw string("Second argument to 'store' not a string");
+		if(name.type!=SIT_STR)throw string("Second argument to 'store' not a string");
 		variables[name.strval]=move(S.back());
 		S.pop_back();
 	}},
 	{"get",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("get",1)
 		Stackitem name=move(S.back()); S.pop_back();
-		if(!name.isstr)throw string("Argument to 'get' not a string");
+		if(name.type!=SIT_STR)throw string("Argument to 'get' not a string");
 		S.push_back(variables[name.strval]);
 	}},
 	//leaves variable with value 0
 	{"swapoutvar",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("swapoutvar",1)
 		Stackitem name=move(S.back()); S.pop_back();
-		if(!name.isstr)throw string("Second argument to 'swapoutvar' not a string");
-		S.push_back(move(variables[name.strval]));
-		variables[name.strval].intval=0;
+		if(name.type!=SIT_STR)throw string("Second argument to 'swapoutvar' not a string");
+		auto it=variables.find(name.strval);
+		if(it==variables.end()){
+			variables.emplace(piecewise_construct,
+				forward_as_tuple(name.strval),
+				forward_as_tuple());
+			it=variables.find(name.strval);
+		}
+		S.push_back(move(it->second));
+		it->second.intval=0;
+		it->second.type=SIT_INT;
 	}},
 	{"enterscope",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("enterscope",0)
@@ -285,7 +325,7 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 	{"roll",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("roll",1)
 		Stackitem ns=move(S.back()); S.pop_back();
-		if(ns.isstr)throw string("Argument to 'roll' not a number");
+		if(ns.type!=SIT_INT)throw string("Argument to 'roll' not a number");
 		int n=ns.intval;
 		if(S.size()<2)return;
 		bool negative=n<0;
@@ -314,45 +354,114 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("stridx",2)
 		Stackitem idx=move(S.back()); S.pop_back();
 		const Stackitem &str=S.back();
-		if(!str.isstr)throw string("First argument to 'stridx' not a string");
-		if(idx.isstr)throw string("Second argument to 'stridx' not a number");
-		if(idx.intval<0||idx.intval>=(int)str.strval.size())throw string("Index argument to 'stridx' out of range");
+		if(str.type!=SIT_STR)throw string("Top of stack is not a string in builtin 'stridx'");
+		if(idx.type!=SIT_INT)throw string("Argument to 'stridx' not a number");
+		if(idx.intval<0||idx.intval>=(int)str.strval.size())throw string("Argument to 'stridx' out of range");
 		S.emplace_back(string(1,str.strval[idx.intval]));
 	}},
 	//leaves the string on the stack
 	{"strlen",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("strlen",1)
 		const Stackitem &str=S.back();
-		if(!str.isstr)throw string("Argument to 'strlen' not a string");
+		if(str.type!=SIT_STR)throw string("Argument to 'strlen' not a string");
 		S.emplace_back(str.strval.size());
 	}},
-	//leaves the string on the stack
+	//leaves the string on the stack; `to` is exclusive
 	{"substr",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("substr",3)
 		const Stackitem to=move(S.back()); S.pop_back();
 		const Stackitem from=move(S.back()); S.pop_back();
 		const Stackitem &str=S.back();
-		if(!str.isstr)throw string("First argument to 'substr' not a string");
-		if(from.isstr)throw string("Second argument to 'substr' not a number");
-		if(to.isstr)throw string("Third argument to 'substr' not a number");
+		if(str.type!=SIT_STR)throw string("Top of stack is not a string in builtin 'substr'");
+		if(from.type!=SIT_INT)throw string("First argument to 'substr' not a number");
+		if(to.type!=SIT_INT)throw string("Second argument to 'substr' not a number");
 		S.emplace_back(str.strval.substr(from.intval,to.intval-from.intval));
 	}},
 	{"chr",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("chr",1)
-		Stackitem ascii=move(S.back()); S.pop_back();
-		if(ascii.isstr)throw string("Argument to 'chr' not a number");
-		S.emplace_back(string(1,ascii.intval));
+		if(S.back().type!=SIT_INT)throw string("Argument to 'chr' not a number");
+		S.back().type=SIT_STR;
+		S.back().strval=string(1,S.back().intval);
 	}},
 	{"ord",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("ord",1)
-		if(!S.back().isstr)throw string("Argument to 'ord' not a string");
-		S.back().isstr=false;
+		if(S.back().type!=SIT_STR)throw string("Argument to 'ord' not a string");
+		S.back().type=SIT_INT;
 		S.back().intval=(int)S.back().strval[0];
-		S.back().strval="";
+		S.back().strval.clear();
+	}},
+	{"mkarray",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("mkarray",0)
+		S.emplace_back(Stackitem(vector<Stackitem>()));
+	}},
+	//mkarray prefill
+	{"mkarrayp",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("mkarrayp",1)
+		const Stackitem nitems=move(S.back()); S.pop_back();
+		if(nitems.type!=SIT_INT)throw string("Argument to 'mkarrayp' not a number");
+		if(nitems.intval<0)throw string("Negative argument to 'mkarrayp'");
+		BUILTIN_GUARD_STACKSIZE("mkarrayp: prefill",nitems.intval);
+		Stackitem res((vector<Stackitem>()));
+		res.arrval.reserve(nitems.intval);
+		const int sz=S.size();
+		for(int i=sz-nitems.intval;i<sz;i++)res.arrval.push_back(move(S[i]));
+		S.erase(S.end()-nitems.intval,S.end());
+		S.push_back(move(res));
+	}},
+	//leaves the array on the stack
+	{"arridx",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("arridx",2)
+		const Stackitem idx=move(S.back()); S.pop_back();
+		if(idx.type!=SIT_INT)
+			throw string("Argument to 'arridx' not a number");
+		if(S.back().type!=SIT_ARR)
+			throw string("Top of stack is not an array in builtin 'arridx'");
+		if(idx.intval<0||idx.intval>=S.back().arrval.size())
+			throw string("Argument to 'arridx' out of range");
+		S.push_back(S.back().arrval[idx.intval]);
+	}},
+	//leaves the array on the stack
+	{"arrlen",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("arrlen",1)
+		if(S.back().type!=SIT_ARR)
+			throw string("Top of stack is not an array in builtin 'arrlen'");
+		S.emplace_back(S.back().arrval.size());
+	}},
+	//leaves the array on the stack, obviously
+	{"push",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("push",2)
+		if(S[S.size()-2].type!=SIT_ARR)
+			throw string("Top of stack is not an array in builtin 'push'");
+		S[S.size()-2].arrval.push_back(move(S.back()));
+		S.pop_back();
+	}},
+	//leaves the array on the stack, obviously
+	{"pop",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("pop",1)
+		if(S.back().type!=SIT_ARR)
+			throw string("Top of stack is not an array in builtin 'pop'");
+		S.back().arrval.pop_back();
+	}},
+	{"rand",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("rand",0)
+		assert(RAND_MAX==0x7fffffff);
+		S.emplace_back(rand());
+	}},
+	//`to` exclusive
+	{"randr",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
+		BUILTIN_GUARD_STACKSIZE("rand",2)
+		assert(RAND_MAX==0x7fffffff);
+		const Stackitem from=move(S.back()); S.pop_back();
+		const Stackitem to=move(S.back()); S.pop_back();
+		if(from.type!=SIT_INT)throw string("First argument to 'randr' not a number");
+		if(to.type!=SIT_INT)throw string("Second argument to 'randr' not a number");
+		if(to.intval<=from.intval)throw string("Arguments to 'randr' form an empty range");
+		const int rval=rand();
+		S.emplace_back(rval%(to.intval-from.intval)+from.intval);
 	}},
 	{"sleep",[](vector<Stackitem> &S,unordered_map<string,Stackitem> &variables){
 		BUILTIN_GUARD_STACKSIZE("sleep",1)
-		if(S.back().isstr)throw string("Argument to 'sleep' not a number");
+		if(S.back().type!=SIT_INT)throw string("Argument to 'sleep' not a number");
 		usleep(S.back().intval);
 		S.pop_back();
 	}},
@@ -360,8 +469,8 @@ unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stack
 		BUILTIN_GUARD_STACKSIZE("stackdump",0)
 		cerr<<"STACKDUMP: ";
 		for(const Stackitem &si : S){
-			if(si.isstr)cerr<<'"'<<si.strval<<"\" ";
-			else cerr<<si.intval<<' ';
+			if(si.type==SIT_STR)cerr<<'"'<<si.strval<<"\" ";
+			else cerr<<to_string(si)<<' ';
 		}
 		cerr<<endl;
 	}},
diff --git a/postrun.cpp b/postrun.cpp
index eda3714..2c3c97f 100644
--- a/postrun.cpp
+++ b/postrun.cpp
@@ -2,6 +2,7 @@
 #include <fstream>
 #include <vector>
 #include <string>
+#include <sys/time.h>
 
 #include "runtime.h"
 
@@ -32,6 +33,11 @@ int main(int argc,char **argv){
 		cerr<<"Could not open file '"<<argv[1]<<"'"<<endl;
 		return 1;
 	}
+
+	struct timeval tv;
+	gettimeofday(&tv,NULL);
+	srand(tv.tv_sec*1000000+tv.tv_usec);
+
 	//string source=readfile(srcf);
 	try {
 		const vector<string> tokens=tokenise(srcf);
diff --git a/runtime.cpp b/runtime.cpp
index 98ae245..19108cd 100644
--- a/runtime.cpp
+++ b/runtime.cpp
@@ -1,10 +1,12 @@
 #include <iostream>
+#include <sstream>
 #include <vector>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
 #include <functional>
 #include <cstring>
+#include <cassert>
 
 #include "runtime.h"
 
@@ -15,23 +17,67 @@ inline bool isextword(char c){return isword(c)||isdigit(c);}
 inline bool isoperator(char c){return (bool)strchr("+-*/%&|~^!=><{}",c);}
 
 
-Stackitem::Stackitem(void):isstr(false),intval(0){}
-Stackitem::Stackitem(int _i):isstr(false),intval(_i){}
-Stackitem::Stackitem(const string &_s):isstr(true),strval(_s),intval(0){}
-Stackitem::Stackitem(const Stackitem&)=default;
-Stackitem::Stackitem(Stackitem &&other):isstr(other.isstr),strval(move(other.strval)),intval(other.intval){
-	other.isstr=false;
+Stackitem::Stackitem(void){}
+
+Stackitem::Stackitem(int _i):type(SIT_INT),intval(_i){}
+Stackitem::Stackitem(const string &_s):type(SIT_STR),strval(_s){}
+Stackitem::Stackitem(const vector<Stackitem> &_a):type(SIT_ARR),arrval(_a){}
+
+Stackitem::Stackitem(const Stackitem &other)=default;
+Stackitem::Stackitem(Stackitem &&other):type(other.type),strval(move(other.strval)),intval(other.intval),arrval(move(other.arrval)){
+	other.type=SIT_INT;
+}
+
+Stackitem& Stackitem::operator=(const Stackitem &other){
+	type=other.type;
+	strval=other.strval;
+	intval=other.intval;
+	arrval=other.arrval;
+	return *this;
 }
-Stackitem& Stackitem::operator=(const Stackitem&)=default;
 Stackitem& Stackitem::operator=(Stackitem &&other){
-	isstr=other.isstr;
+	type=other.type;
 	strval=move(other.strval);
 	intval=other.intval;
-	other.isstr=false;
+	arrval=move(other.arrval);
+	other.type=SIT_INT;
 	return *this;
 }
-Stackitem::operator bool(void) const{return (isstr&&strval.size())||(!isstr&&intval);}
-bool Stackitem::operator==(const Stackitem &other) const{return isstr==other.isstr&&(isstr?strval==other.strval:intval==other.intval);}
+
+Stackitem::operator bool(void) const{
+	return (type==SIT_INT&&intval)||
+	       (type==SIT_STR&&strval.size())||
+	       (type==SIT_ARR&&arrval.size());
+}
+
+bool Stackitem::operator==(const Stackitem &other) const{
+	if(type!=other.type)return false;
+	if(type==SIT_INT)return intval==other.intval;
+	if(type==SIT_STR)return strval==other.strval;
+	assert(type==SIT_ARR);
+	auto sz=arrval.size();
+	if(sz!=other.arrval.size())return false;
+	for(int i=0;i<sz;i++)if(arrval[i]!=other.arrval[i])return false;
+	return true;
+}
+bool Stackitem::operator!=(const Stackitem &other) const{
+	return !(*this==other);
+}
+
+string to_string(const Stackitem &si){
+	if(si.type==SIT_ARR){
+		stringstream ss;
+		ss<<'[';
+		const auto sz=si.arrval.size();
+		for(unsigned int i=0;i<sz;i++){
+			if(i!=0)ss<<',';
+			ss<<to_string(si.arrval[i]);
+		}
+		ss<<']';
+		return ss.str();
+	} else if(si.type==SIT_STR)return si.strval;
+	else return to_string(si.intval);
+}
 
 
 extern const unordered_map<string,function<void(vector<Stackitem>&,unordered_map<string,Stackitem>&)>> builtins;
diff --git a/runtime.h b/runtime.h
index 1a49300..1b20329 100644
--- a/runtime.h
+++ b/runtime.h
@@ -6,21 +6,37 @@
 
 using namespace std;
 
+enum Stackitemtype{
+	SIT_INT,
+	SIT_STR,
+	SIT_ARR
+};
+
 struct Stackitem{
-	bool isstr;
+	Stackitemtype type=SIT_INT;
 	string strval;
-	int intval;
+	int intval=0;
+	vector<Stackitem> arrval;
 
 	Stackitem(void);
-	Stackitem(int _i);
-	Stackitem(const string &_s);
+
+	Stackitem(int _i); //int init
+	Stackitem(const string&); //string init
+	Stackitem(const vector<Stackitem>&); //array init
+
 	Stackitem(const Stackitem&);
 	Stackitem(Stackitem &&other);
+
 	Stackitem& operator=(const Stackitem&);
 	Stackitem& operator=(Stackitem &&other);
+
 	explicit operator bool(void) const;
+
 	bool operator==(const Stackitem &other) const;
+	bool operator!=(const Stackitem &other) const;
 };
 
+string to_string(const Stackitem&);
+
 vector<string> tokenise(istream &stream);
 void run(vector<string> T);