OneMenu

HAPI-based composable menu system for embedded targets. Zero dynamic allocation, zero-overhead output chain, streaming-first (no host framebuffer). Tested on AVR, ESP32, and Linux native.

HAPI Compatibility: Updated for new Check/Apply/ApplyPack API (2026-Q2)

See docs/oneMenu.md for the full user guide (fields, layout, navigation, input, output, actions, patterns).

Features

• Composable output chain: format + printer + cursor + raw device assembled at compile time
• Multiple simultaneous outputs (OLED, LCD, serial, web)
• Partial updates: only redraws changed items
• Navigation: tree menus, wrap/no-wrap, enter/esc/up/down
• Data items: editable numeric and string fields
• Web output: XML + XSLT, live navigation via browser
• Runtime item lookup by compile-time Id<>: find<>/find() walk the menu tree (title, chain, and nested bodies) and return a real reference to the tagged item

Finding items by Id<>

Tag any item with Id<V> and look it up later — from an action callback, for example — to toggle, enable, or otherwise mutate it at runtime:

enum ids { op3_id };
auto mainMenu = menuDef<WrapNav>(
ItemDef<Text>{"Main menu"},
staticBody(
ItemDef<Action<action::op2>, Text>{"Option 2"},
ItemDef<Id<ids::op3_id>, Action<action::op3>, Watch<EnDis<false>>, Text>{"Option 3"}
// ...
)
);
// "Option 2" toggles "Option 3"'s enabled state at runtime:boolaction::op2(Sz) {
auto& op3 = mainMenu.find<SameAs<Id<ids::op3_id>>>(); // or: mainMenu.find(byId<ids::op3_id>)
op3.enable(!op3.enabled());
returntrue;
}

find<> searches the whole tree — a submenu's own Id<>, its title, or anything nested arbitrarily deep in its body — and is a compile error if the tag isn't found anywhere.

Output devices

Header	Device
IO/IOP/oledOut.h	SSD1306 OLED via OneIO
IO/IOP/lcdOut.h	HD44780 character LCD via OneIO
IO/arduino/serialOut.h	Arduino Serial
IO/arduino/webOut.h	ESP32 WebServer — streams XML + XSLT
IO/streamOut.h	std::ostream (native/Linux)

Formats

Header	Target	Output
fmt/textFmt.h	All	Plain text, one line per item
fmt/ansiFmt.h	Linux/native	ANSI color, cursor positioning, partial repaint
fmt/gfxFmt.h	OLED/pixel display	Pixel-level layout, rounded selection, big title
fmt/xmlFmt.h	Web/serial	XML with CDATA-wrapped labels; paired with menu.xsl
fmt/jsonFmt.h	Web/serial/debug	JSON object per item, all attributes as properties
fmt/htmlFmt.h	Web	HTML fragment

Format layers slot into OutDef<Printer, **Fmt**, DataParser<>, Cursor<>, Device, Pos, Area>.

Quick start

#include<oneMenu/oneMenu.h>
#include<oneMenu/menu/IO/IOP/oledOut.h>
#include<oneIO/display/i2cOled.h>usingnamespaceoneMenu;usingnamespaceoneIO::display;using MyOled = I2cOledWire<Wire, SDA, SCL>;
namespaceaction {
boolop2(Sz) { /* ... */returntrue; }
}
auto mainMenu = menuDef<WrapNav>(
ItemDef<Text>{"Main menu"},
staticBody(
ItemDef<StaticText<&text::op1>>{},
ItemDef<Action<action::op2>, StaticText<&text::op2>>{}
)
);
NavDef<TreeNav<>, Root<mainMenu>> nav;
OledDisplay<MyOled, GfxFmt<2, 0, true>> oledDisplay;
voidsetup() {
MyOled::begin();
oledDisplay.clear();
oledDisplay.lockMode(LockMode::None);
nav.printTo(oledDisplay);
}
voidloop() {
nav.in(in);
if(nav.changed(oledDisplay)) {
nav.printTo(oledDisplay);
nav.sync(oledDisplay);
}
}

LCD output

#include<oneMenu/menu/IO/IOP/lcdOut.h>
#include<oneIO/display/i2cLcd.h>using MyLcd = oneIO::display::I2cLcd<AvrTwiMaster<>, 0x27, 20, 4>; // TwiMaster, Addr, Cols, Rows
LcdOut<MyLcd> lcdDisplay;
// setup: MyLcd::begin(); lcdDisplay.clear(); lcdDisplay.lockMode(LockMode::None);

Web output (ESP32)

#include<oneMenu/menu/IO/arduino/webOut.h>
WebDisplay webDisplay;
WebOut::begin(webServer);
webServer.on("/", []() {
webServer.setContentLength(CONTENT_LENGTH_UNKNOWN);
webServer.send(200, "text/xml", "");
webServer.sendContent("<?xml version=\"1.0\"?>\n<?xml-stylesheet type=\"text/xsl\" href=\"/menu.xsl\"?>\n");
webDisplay.lockMode(LockMode::None);
nav.printTo(webDisplay);
});
webServer.on("/menu.xsl", []() { webServer.send(200, "text/xsl", WebOut::xsl()); });