08. Text and I/O

Froth has Text values, but it does not pretend to be a desktop scripting language. Text exists for names, messages, small payloads, simple parsing, and board-facing protocols. File systems and rich Unicode text processing are not part of the first public language surface.

Text Values

A text literal is immutable:

label is "ready"
label

Text is byte-oriented in the current profile. Unicode semantics are out of scope. That is a deliberate choice for a small device-first language.

Where text operations are available, they should be understood as byte operations. A parser that looks at "L68" is looking at bytes, not grapheme clusters or locale-sensitive characters.

Prompt Output

The prompt prints the result of top-level expression evaluation:

"hello"
1 + 2

Definitions need not print a result:

to hello [
  "hello"
]

Call the code when you want the value:

hello:

For inspection, prefer the inspection words over improvised print debugging:

show @hello
see @hello
info @hello

Those tell you what is bound, not just what a single expression happened to return.

Text In Small Parsers

Text is enough for compact local parsing exercises:

to digit with byte [
  byte - 48
]

A full line parser usually keeps an index and accumulator in locals or top-level state. Keep those helpers small. On a microcontroller, a readable byte-at-a-time parser is usually better than hiding the work behind a large general library.

I/O Is Board Surface

Froth separates language values from board I/O. GPIO, ADC, display, I2C, UART, and timing are base-image or board-provided bindings:

gpio.read: BOOT_BUTTON
adc.read: A0
grid.show:
uart.write: 65, console

Not every board exposes every I/O family. The Froth Machine exposes GPIO, ADC, the TM1629 display layer, joystick helpers, and knob helpers. The source-level ESP32 DevKit V1 board also carries I2C, UART, and LEDC bindings.

That split keeps examples honest. A tutorial can be device-first without implying that every board has every peripheral.

Next: Talking to hardware .