I have a string:

string s="digitalWrite(8,LOW);"

Is there any way to run it as a code?

  • Not an easy way, since you basically would need to write a C/C++ interpreter library for this. I don't know of such a library. Why do you need to do this? What are you trying to achieve?
    – chrisl
    Commented Mar 14, 2020 at 10:30
  • To run commands that will be saved in external eeprom
    – rktech
    Commented Mar 14, 2020 at 10:38
  • Do you really have such complex programs to save there, that you need C syntax text there? Instead you could build your own command structure, which can be way easier to interpret. What commands do you need to save in the EEPROM?
    – chrisl
    Commented Mar 14, 2020 at 10:52
  • @chrisl thank you, I forgot that I can do it like this
    – rktech
    Commented Mar 14, 2020 at 11:34

1 Answer 1


This is actually pretty simple:

if (s == "digitalWrite(8,LOW);") {

Obviously, it will not work is s contains any other string... If you want something more general, that is able to interpret a wide range of possible commands, you will have to define a language, and write an interpreter for that language. From the example you give, it seems you would like your language to look like C++. This is most likely a bad design choice. If you want an interpreter that understands the whole C++ language: forget it. You will never fit something this big into an Arduino Uno.

Here is, for inspiration, a very simple interpreter I wrote that understand the following commands:

mode <pin> <mode>: pinMode()
read <pin>: digitalRead()
aread <pin>: analogRead()
write <pin> <value>: digitalWrite()
awrite <pin> <value>: analogWrite()
echo <value>: set echo off (0) or on (1)

You can use it a basis for writing your custom interpreter. Otherwise you can do a Web search for “Arduino interpreter”: you should be able to find interpreters implementing a wide variety of languages, including compact binary languages (Firmata), Forth (another one), Lisp, Basic, and even a C-like language.

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