add startswith

bootstrap/ISBPL.java

@@ -446,8 +446,7 @@ public class ISBPL {
                 break;
             case "getos":
                 func = (Stack<ISBPLObject> stack) -> {
-                    // TODO: This is not done yet, and it's horrible so far.
-                    stack.push(toISBPLString("linux"));
+                    stack.push(toISBPLString(System.getProperty("os.name")));
                 };
                 break;
             case "mktype":

std.isbpl

@@ -462,3 +462,24 @@ func ] {
     }
     pop array
 }
+
+func astartswith {
+    def match _array =match
+    def str _array =str
+
+    str alen match alen lt if {
+        0 2 stop
+    }
+    str alen match alen eq if {
+        str match eq 2 stop
+    }
+    def i 0 =i
+    while { i match alen lt } {
+        str i aget match i aget eq not if {
+            0 3 stop
+        }
+        i inc
+    }
+
+    1
+}

stream.isbpl

@@ -15,6 +15,10 @@ def STREAM.write           iota =STREAM.write
 
 def STREAM.create.server iota =STREAM.create.server
 
+func STREAM.stdin {
+    getos strlowercase "win" astartswith dup if { "conIN$" } not if { "/dev/stdin" }
+}
+
 func stream.readline {
     def id =id
     def byte 0 =byte