Class StrictAbsent

java.lang.Object

org.ek9lang.compiler.phase7.support.StrictAbsent

public final class StrictAbsent
extends Object

THE compile-time half of strict-absent mode (Steve, decision 5, 2026-10-07: "a residual absence PANICS, always").

Every compiled absence TEST - the IS_NULL at the head of ? (and so of guards, ?: and the comparison coalescing operators) and of ?? - answers a null quietly today: ? says false, ?? takes its right-hand side. In a well-typed program that null is unreachable (the front end proves every read is preceded by a write), so meeting one means the proof has a hole. When the COMPILING JVM has -Dek9.absent.strict=true (AbsentValue.STRICT_PROPERTY - the property is read the way IRAnalysis reads ek9.arcBalance.strict), the null branch of each such test begins with a Panic (PanicThrowInstrs) whose message is AbsentValue.message(String, String). Off (the default) this emits nothing, so the IR - and every @IR/@BYTECODE golden - is unchanged.

🔑 :=?'s own IS_NULL is NOT a strict site, deliberately: on the never-written slot of x as T? the null IS the case :=? exists for (it writes), and the front end credits it as the write (controls g25/a10 in docs/language-design/absence-evidence/controls). Callers say which kind of test they are building; nothing else may decide it.

The runtime half - the null tolerances in ek9-lang - reads the same property on the JVM that RUNS the program (see AbsentValue). Back ends: the Panic is ordinary IR, so the LLVM back end gets it with no work.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	StrictAbsent.Observer	What observed an absent value, and where: the operator, and the source location named in the Panic message.

Method Summary

Modifier and Type	Method	Description
static void	emitIfEnabled(IRGenerationContext stackContext, List<IRInstr> instructions, StrictAbsent.Observer observer, DebugInfo debugInfo)	In strict-absent mode, append the Panic to instructions - the start of the branch a compiled absence test takes on a null.
static boolean	isEnabled()	Is strict-absent mode on for this compilation?
static String	message(StrictAbsent.Observer observer)	THE strict-absent Panic message for a compiled absence test.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

isEnabled

public static boolean isEnabled()

Is strict-absent mode on for this compilation?

message

public static String message(StrictAbsent.Observer observer)

THE strict-absent Panic message for a compiled absence test.

emitIfEnabled

public static void emitIfEnabled(IRGenerationContext stackContext,
 List<IRInstr> instructions,
 StrictAbsent.Observer observer,
 DebugInfo debugInfo)

In strict-absent mode, append the Panic to instructions - the start of the branch a compiled absence test takes on a null. Otherwise append nothing.

Parameters:

stackContext - for temp names and the current scope

instructions - the null branch being built

observer - what observed the null, and where

debugInfo - the debug information carried by the emitted instructions