Migrating from EZ-Script to JavaScript
Semicolon Line Endings
When writing EZ-Script code, at the end of the line you simply press <enter> and start coding on the next line. However, in JavaScript, it is recommended to terminate the line with a semicolon ; character. With the ARC JavaScript compiler, it is not mandatory to do it, but you will find most code examples will have the semicolon at the end of the line.
Examples
EZ-Script Example
print("This is some text")
print("This is another line of text")
JavaScript Example
print("This is some text");
print("This is another line of text");
*Note: Notice the semicolon at the end of the lines in JavaScript. Again, it's not mandatory, but it is recommended for proper JavaScript compliance.
Why Semicolons?
Traditionally, a semicolon has been common across many programming languages to tell the compiler the end of the command. This is because many commands can be included on the same line with JavaScript. It is not recommended to do this because it is messy to read, but some people program this way.Example Of Many Commands On One Line
print("Hello"); print("World");
Wow that is totally great info to know, thanks!
Thanks for this Tutorial @DJ. It will be invaluable as I change over my many scripts from EZ Script to JavaScript! I'm excited to see how my robot's arm servo react to the new faster language. I have some pretty complex scripts (for me anyway. LOL).
I think you'll find that the new scripts you write will be even smaller and faster. Probably easier to read as well. I can always help you change some over if you post one. That'll give you examples of how the difference would be.
But just to be clear, the EZ scripts should still mostly work in Arc? I tried 2 that still worked no conversion. Just slower most likely.
Yeah, EZ-Script works in ARC. This is a tutorial to help people migrate to a faster and more feature-rich language.
Wow @DJ. That's an amazing offer. Thanks! I'll post one soon. I think I have covid now and need to get past that first. Can't quite thing straight right now. LOL.
Oh boy, it seems everyone is getting covid these days. I'm feeling left out. I hope you're doing well and binge-watching a lot of tv! Drink soup and dream about robots.
Thanks DJ. I'm coming to the end of it I hope. Feeling better. Don't feel left out. Only good thing about this is now I have some antibodies for a while. LOL. Stay healthy!
That's what super heros are made of!
Actually i was adding some script codes for my Init servos start up and other start up functions, then realized I used EZ script instead of Javascript. Since Javascript is way faster ,what is the easy way to convert the EZ script over to Javascript? right now it just wants to delete the whole EZ script when I move into Javascript window. Like if I copy and paste it in, will it convert? I guess I can just start over line by Line with the cheat helper Edit.... I think I had a similar question last week about using my old EZ scripts and did you point out some tutorial Link? I seem to have forgot where.
*Note: I moved your question to the appropriate thread because it was asked on a feature request for Blockly copy and paste
The windows Copy and Paste command will copy the text. There is no way to "convert code" when pasting. It will merely paste what is copied. Once you paste the EZ-Script into the JavaScript window, you can edit the code to make it JavaScript syntax.
Ahh yes That was what I was looking for thanks again, sorry for asking twice,LOL!
How to include a javascript library ?
There used to be an option for that. Hmmm. I can't seem to find it now. I'll have to take a better look as I don't see it in the documentation on the support section.
....just stumbled onto this...thank you so much.
OK, I'm having trouble wrapping my mind around converting my EZ Script to JavaScript. I do think I understand some of the basics ways to write in JS like loops, classes and variables. However I I have a very complicated but working EZ script I wrote a few years ago I'm trying to convert to JS but I don't understand some of the proper ways to write commands.
Here are a couple of the commands I'm having trouble understanding. I'll show the EZ Script command that works and try to show the way I think the JS command will work. If some one can guide me to the correct syntax I would be grateful:
In this first example I am sending a command through EZB 2, Uart 2 to a Kangaroo Motor controller. The Roo's command is inside the " ". It states which channel on the Roo to start the move on, the position to move to and at what speed. The next command in the line, 0x0d, is the ASCII value for the Return Key on a keyboard. The Roo needs this to accept the command:
Below is what I think the JS Syntax should be??? Notice the 0x0d ASCII value and the uart port and EZB index numbers. Do I need those quote marks? How close am I in being correct?
Now, My next big problem. How to split and GetCharAt with JS. When the I request a position and the Kangaroo motor controller returns this position to ARC through an EZB Uart, it comes back looking like this: Pxxx or pxxx. Their will be either a upper or lower case P followed by the position number (xxx). An upper case P means the motor is still moving and a lower case means it's stopped. I wrote an EZ script that puts this returned value into a variable, splits the P from the position number, tells me if the P is upper or lower case and what the position number is. The way I'm using this script is that I ignore the P and only need to position number. However I need to split the P from the returned value and ignore it or the script wont work:
Then I have the EZ Script decide if the motor has fully deployed the payload and it's safe to continue or it needs to go loop back and do everything over again until the payload in in position. It then sets a global variable which tells a different script that is waiting on this that i's safe to proceed. This EZ script loops until that safe position is reached (805) and sets that variable.
As you can see above this EZ Script is commanding two motors through one Kangaroo, I have no idea how to do the above with JS. I know I'll have to figure out a different way to do the looping as JS does not use GOTO and labels like this. If I could get some help with splitting returned characters and getting characters at a certain place this would be very helpful.
Here's the complete EZ Script for reference if it helps: Be kind. It's probably messy. LOL. Any ideas or advice are very welcomed that will improve it or help with conversion to JS. Thanks in advance!
OK, I decided I was biting off to much at one time. I decided to just concentrate on trying one JS command at a time to see if I can get stuff working. I'm starting with the Uart command.
I'm making progress on making things work like checking if variables exist and initializing Uart ports. I'm been able to run several commands without errors so I think I'm catching on. However I've hit a wall.
After initializing the proper Uart port I decided to try to move a motor by sending a command through the port to the Kangaroo Motor controller. Like I mentioned and showed above I've been able to do this using EZ Script. I followed @DJ's tutorial and the online JavaScript API here on this forum in the support section with no luck. The script ran and compilated with out an error but the Kangaroo didn't respond. I think the problem is how I'm sending the string to the roo. It needs a Return (enter) keyed after the position and speed command and I don't think I have that properly written in JS. Here's the EZ Script command that works makes the Kangaroo respond. Notice the 0x0d (ASCII for carrage return) :
Here's the code I wrote in JS that I think is close (from what I read in the JavaScript API in the support section). The script completes and seems to send it through the UART. Again, I don't think I have the 0x0d part of string written properly. But I don't really know.
Any help figuring this out would be welcomed.
I don't know if this is a dumb suggestion but I just noticed that Chat A.I. can write Java script code for you if you just ask what you need done. I looked at some examples that seem legit. Sorry if that is no help. Your problem stems from the Kangaroo so, Depends if A.I. can find previous solutions in other forum posters around the internet.
Thanks my friend. I've never used any chat AI programs. I wouldn't know how to start. However you gave me a good idea. I'll contact the Dimension Engineering who make the Kangaroo. Maybe they can tell me a way to send the simple serial command for speed, position and the needed "return" key using JavaScript. I had this same issue when I started commanding the Roo using EZ Script. It's that "return" (or Enter) key, 0x0d, that I cant figure how to get into the JavaScript command.
HAHA!! Got it!! Yes!!
I found the answer on the Stackoverflow forum. A guy there was working on a different problem he was having with a Python script that controls his Kangaroo. I looked through his script and saw in his Python script that he has a \r inside his double quotes and the end of his string. I inserted it and it works!!
So the proper script that works (once the UART initialized) is as follows. Note the \r at the end of line 1:
var str = "2,p805 s300\r"; UART.hardwareUartWrite(2,str.length,2); UART.hardwareUartWriteString(2,str,2);
Great news Dave, Glad you solved it and have a great Easter!
Thanks my friend!
I've been making slow but sure progress with converting my EZ Script I posted above into Javascript. I'm able to do most basic things now like looping and If statements. I've also been able to send and commands to my Kangaroo using the UART. commands. I'm pretty excited at how little syntax I need and how fast it appears to be.
I do have a question about one of the UART. commands that I hope some one could help explain. When I'm asking to read bytes from the UART buffer I seem to have two commands available:
When I run these commands with different scripts I get the same returned answers: Script 1 using UART.hardwareUartReadStringAvailable
Script 1 Answers:
Script 2 using UART.hardwareUartReadString
Script 2 Answers:
As I said, I get the same answers. The only differance I can see is that in UART.hardwareUartReadString I need to state how many bites I am expecting. This has proven a problem because I've notices that sometime the buffer has more then the usual 7 bytes available. Mostly after a failed read.
Can someone explain which is the best command to use and/or why I would have to state how many bytes I'm expecting if I use UART.hardwareUartReadString ?
Thanks!
Well, it's been a learning experience for me. However with the help of the tutorial at the top of this page, the Synthiam JavaScript api at the link provided in that same tutorial along with many, many tips throughout the internet to JS scripting sites I was able to convert the EZ script I posted above to JavaScript.
As I said, I'm a novice to JS and mostly understand how to write a working script in EZ Script. I'm starting to understand some of the basic nuances of JS and have made a converted working script. It looks much neater and runs much smoother and faster then my original EZ Script. At this point I'm satisfied with my result but after seeing how much I don't know about JS I'm not sure it's done as well as possible. However it works nice for my needs and I'm happy. LOL.
My intent is to move two carriages that are powered and controlled by a Sabertooth / Kangaroo motor controller. They must move out of an enclosed robot torso until they reach a save point before the arm servos can start moving around. I could just send the carriages out and hope they reach a safe point but if the arms starts moving around before they are clear they will destroy themselves. This script has a built in fail safe to keep that from happening. It monitors the progress of the carriage motor's encoders, Then when it reaches safety it sets a global variable that tells a different waiting script (it's an EZ Script at this point) that it's safe to start moving the arm servos.
Here it is for your enjoyment. LOL. :
Here's the console readout: