Web IDE Verify Anomaly

General
1

There appears to be no category for the web IDE so General it is.

I ran across a strange occurrence today using a simple if, else if routine. I have narrowed it down to the following. I have removed any variable names and just used the number 1 for clarity. Using a boolean or integer for the test results in the same error.

int a;
void setup() {
}

void loop() {
    if (1) {
        a++;
    }
    else if (1) {
        a--;
    }
}

This gives me the following error.

"if_else_test.cpp:5:1: error: expected unqualified-id before 'else’
else if (1);
^

If I make a simple change to the else if test like this

int a;

void setup() {
}
void loop() {
    if (1) {
        a++;
    }
    else if (!1) {
        a--;
    }
}

I get the coveted “Code verified! Great work.”

Is this something I’m not understanding or is this an IDE problem?

I am programming a photon using 0.4.9

2

That’s a “well” known issue due to the wiring preprocessor.

If you use

#pragma SPARK_NO_PREPROCESSOR
#include "Particle.h"

int a;
void setup() {
}

void loop() {
    if (1) {
        a++;
    }
    else if (1) {
        a--;
    }
}

it builds too.

It’s not actually due to the (1) but to the else if. If you write

    if (1) {
        a++;
    }
    else {
      if (1) {
        a--;
      }
    }

It also builds.

Don’t ask … :confused:

2 Likes
3

I guess that settles it for me. Dump the preprocessor.

Other than forcing programming to adhere to a more structured format and including application.h, which is good anyways, is there any disadvantage to not using the preprocessor?

4

When you are not using the preprocessor, you are not writing in “Wiring,” the simplified version of C that Arduino uses. You are instead writing in straight C (or C++).

That means you need to provide function prototypes and any other forward references just like you normally do in C.

3 Likes
5

Since I have never played with or in the Arduino ecosystem and just discovered that all of my programs actually compile with #pragma SPARK_NO_PREPROCESSOR added it must mean that I am actually learning something about C/C++ programming.

For me that’s an accomplishment! :stuck_out_tongue_winking_eye: Now if I could only stop forgetting those darn semicolons. :flushed: