unix_time and convert_date (#332)

* very simple stuff

* added unix_date and imporved unix_time

* Update docs/scarpet/api/Auxiliary.md

Co-authored-by: gnembon <41132274+gnembon@users.noreply.github.com>

* Update Full.md

* Dont 100% work, but It'll do untl I fix tomorrow

* works, I think

* changeing weekdays

* removing weird stuff I didnt mean to do

* previous commits

* moving to expression.java

because prof.gnembon said

* moving away from LazyFUnctions

cos gnembon doesn't like evaluating somewhere

* updating docs

* tweaks to dates

Co-authored-by: Ghoulboy78 <ghoulboy27@gmail.com>

docs/scarpet/Full.md

@@ -921,6 +921,52 @@ flip_my_world_upside_down();
 print(str('this took %d milliseconds',time()-start_time))
 </pre>
 
+### `unix_time()`
+
+Returns standard POSIX time as a number of milliseconds since the start of the epoch 
+(00:00 am and 0 seconds, 1 Jan 1970).
+Unlike the previous function, this can be used to get exact time, but it varies from time zone to time zone.
+
+### `convert_date(milliseconds)`
+### `convert_date(year, month, date, hours?, mins?, secs?)`
+### `convert_date(l(year, month, date, hours?, mins?, secs?))`
+
+If called with a single argument, converts standard POSIX time to a list in the format: 
+
+`l(year, month, date, hours, mins, secs, day_of_week, day_of_year, week_of_year)`
+
+eg: `convert_date(1592401346960) -> [2020, 6, 17, 10, 42, 26, 3, 169, 25]`
+
+Where the `6` stands for June, but `17` stands for 17th, `10` stands for 10am,
+`42` stands for 42 minutes past the hour, and `26` stands for 26 seconds past the minute,
+and `3` stands for Wednesday, `169` is the day of year, and `25` is a week of year. 
+
+Run `convert_date(unix_time())` to get current time as list.
+
+
+When called with a list, or with 3 or 6 arguments, returns standard POSIX time as a number of milliseconds since the
+ start of the epoch (1 Jan 1970),
+using the time inputted into the function as opposed to the system time.
+
+Example editing:
+<pre>
+date = convert_date(unix_time());
+
+months = l('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
+
+days = l('Mon','Tue','Wed','Thu','Fri','Sat','Sun');
+
+print(
+  str('Its %s, %d %s %d, %02d:%02d:%02d', 
+    days:(date:6-1), date:2, months:(date:1-1), date:0, date:3, date:4, date:5 
+  )
+)  
+</pre>
+
+This will give you a date:
+
+It is currently `hrs`:`mins` and `secs` seconds on the `date`th of `month`, `year`
+
 ### `profile_expr(expression)`
 
 Returns number of times given expression can be run in 50ms time. Useful to profile and optimize your code. 

docs/scarpet/language/SystemFunctions.md

@@ -278,6 +278,52 @@ flip_my_world_upside_down();
 print(str('this took %d milliseconds',time()-start_time))
 </pre>
 
+### `unix_time()`
+
+Returns standard POSIX time as a number of milliseconds since the start of the epoch 
+(00:00 am and 0 seconds, 1 Jan 1970).
+Unlike the previous function, this can be used to get exact time, but it varies from time zone to time zone.
+
+### `convert_date(milliseconds)`
+### `convert_date(year, month, date, hours?, mins?, secs?)`
+### `convert_date(l(year, month, date, hours?, mins?, secs?))`
+
+If called with a single argument, converts standard POSIX time to a list in the format: 
+
+`l(year, month, date, hours, mins, secs, day_of_week, day_of_year, week_of_year)`
+
+eg: `convert_date(1592401346960) -> [2020, 6, 17, 10, 42, 26, 3, 169, 25]`
+
+Where the `6` stands for June, but `17` stands for 17th, `10` stands for 10am,
+`42` stands for 42 minutes past the hour, and `26` stands for 26 seconds past the minute,
+and `3` stands for Wednesday, `169` is the day of year, and `25` is a week of year. 
+
+Run `convert_date(unix_time())` to get current time as list.
+
+
+When called with a list, or with 3 or 6 arguments, returns standard POSIX time as a number of milliseconds since the
+ start of the epoch (1 Jan 1970),
+using the time inputted into the function as opposed to the system time.
+
+Example editing:
+<pre>
+date = convert_date(unix_time());
+
+months = l('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
+
+days = l('Mon','Tue','Wed','Thu','Fri','Sat','Sun');
+
+print(
+  str('Its %s, %d %s %d, %02d:%02d:%02d', 
+    days:(date:6-1), date:2, months:(date:1-1), date:0, date:3, date:4, date:5 
+  )
+)  
+</pre>
+
+This will give you a date:
+
+It is currently `hrs`:`mins` and `secs` seconds on the `date`th of `month`, `year`
+
 ### `profile_expr(expression)`
 
 Returns number of times given expression can be run in 50ms time. Useful to profile and optimize your code. 

src/main/java/carpet/script/CarpetExpression.java

@@ -138,6 +138,7 @@ import net.minecraft.world.dimension.DimensionType;
 import net.minecraft.world.gen.ChunkRandom;
 import org.apache.commons.lang3.tuple.Pair;
 
+import java.util.Date;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;

src/main/java/carpet/script/Expression.java

@@ -43,7 +43,9 @@ import org.apache.commons.lang3.text.WordUtils;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Calendar;
 import java.util.Collections;
+import java.util.GregorianCalendar;
 import java.util.HashMap;
 import java.util.IllegalFormatException;
 import java.util.Iterator;
@@ -1790,6 +1792,66 @@ public class Expression
             return (cc, tt) -> time;
         });
 
+        addLazyFunction("unix_time", 0, (c, t, lv) ->
+        {
+            Value time = new NumericValue(System.currentTimeMillis());
+            return (cc, tt) -> time;
+        });
+
+        addFunction("convert_date", lv ->
+        {
+            int argsize = lv.size();
+            if (lv.size() == 0) throw new InternalExpressionException("'convert_date' requires at least one parameter");
+            Value value = lv.get(0);
+            if (argsize == 1 && !(value instanceof ListValue))
+            {
+                Calendar cal = new GregorianCalendar(Locale.ROOT);
+                cal.setTimeInMillis(NumericValue.asNumber(value, "timestamp").getLong());
+                int weekday = cal.get(Calendar.DAY_OF_WEEK)-1;
+                if (weekday == 0) weekday = 7;
+                Value retVal = ListValue.ofNums(
+                        cal.get(Calendar.YEAR),
+                        cal.get(Calendar.MONTH)+1,
+                        cal.get(Calendar.DAY_OF_MONTH),
+                        cal.get(Calendar.HOUR_OF_DAY),
+                        cal.get(Calendar.MINUTE),
+                        cal.get(Calendar.SECOND),
+                        weekday,
+                        cal.get(Calendar.DAY_OF_YEAR),
+                        cal.get(Calendar.WEEK_OF_YEAR)
+                );
+                return retVal;
+            }
+            else if(value instanceof ListValue)
+            {
+                lv = ((ListValue) value).getItems();
+                argsize = lv.size();
+            }
+            Calendar cal = new GregorianCalendar(0, 0, 0, 0, 0, 0);
+
+            if (argsize == 3)
+            {
+                cal.set(
+                        NumericValue.asNumber(lv.get(0)).getInt(),
+                        NumericValue.asNumber(lv.get(1)).getInt()-1,
+                        NumericValue.asNumber(lv.get(2)).getInt()
+                );
+            }
+            else if (argsize == 6)
+            {
+                cal.set(
+                        NumericValue.asNumber(lv.get(0)).getInt(),
+                        NumericValue.asNumber(lv.get(1)).getInt()-1,
+                        NumericValue.asNumber(lv.get(2)).getInt(),
+                        NumericValue.asNumber(lv.get(3)).getInt(),
+                        NumericValue.asNumber(lv.get(4)).getInt(),
+                        NumericValue.asNumber(lv.get(5)).getInt()
+                );
+            }
+            else throw new InternalExpressionException("Date conversion requires 3 arguments for Dates or 6 arguments, for time");
+            return new NumericValue(cal.getTimeInMillis());
+        });
+
         addLazyFunction("profile_expr", 1, (c, t, lv) ->
         {
             LazyValue lazy = lv.get(0);

src/main/java/carpet/script/value/ListValue.java

@@ -98,6 +98,13 @@ public class ListValue extends AbstractListValue implements ContainerValueInterf
     {
         return ListValue.wrap(Arrays.asList(list));
     }
+    public static ListValue ofNums(Number ... list)
+    {
+        List<Value> valList = new ArrayList<>();
+        for (Number i : list)
+            valList.add(new NumericValue(i.doubleValue()));
+        return ListValue.wrap(valList);
+    }
 
     public static LazyValue lazyEmpty()
     {