mers/gui.mers

lib mers_libs/gui

base = gui_init()
column = base.gui_add(Column: [])

text = column.gui_add(Text: "Welcome to MERS GUI!")

button = column.gui_add(Button: "This is a button.")
second_button = column.gui_add(Button: "This is a second button.")

text_state = -2
second_text = column.gui_add(Text: "press the button above to remove this text!")

while {
    for event gui_updates() {
        switch! event {
            ButtonPressed([int]) {
                e = event.noenum()
                match e {
                    &e.eq(&button) println("First button pressed")
                    &e.eq(&second_button) {
                        // don't match on text_state because we need to change the original from inside the match statement
                        state = text_state
                        match state {
                            // the first, third, fifth, ... time the button is pressed: remove the text
                            text_state.mod(2).eq(0) {
                                if text_state.eq(-2) {
                                    // the first time the button is pressed
                                    text_state = 0
                                    set_title("keep pressing the button!")
                                }
                                second_text.gui_remove()
                            }
                            // the 2nd, 4th, 6th, ... time the button is pressed: add the text back
                            text_state.eq(1) second_text = column.gui_add(Text: "i'm back!")
                            text_state.eq(3) second_text = column.gui_add(Text: "you can't fully get rid of me!")
                            true {
                                second_text = column.gui_add(Text: "i always come back")
                                // restart (set text_state to 0)
                                text_state = -1
                            }
                        }
                        text_state = text_state.add(1)
                    }
                    true println("A different button was pressed (unreachable)")
                }
            }
        }
    }
    []
}