Cx Dev Log — 2026-04-12

#cx #programming

Two notable changes hit submain today, breaking a three-day streak of quiet. The Phase 10 IR lowering now covers infinite loop, break, and continue, and a fresh process document defines the agent's operating approach. While both await integration into main, these updates provide key insights into language design and team workflow.

Extended Loop Constructs in IR

The real highlight is the bcd49f2 commit. Modifications in src/ir/lower.rs, with 215 lines added and 16 removed, introduce a LoopContext structure that guides IR transformations to support infinite loops and related constructs like break and continue.

To be specific:

lower_loop Function: This creates a control flow graph (CFG) for infinite loops by setting up an unconditional jump into the loop's header, executing the loop body, and terminating at an exit block. This ensures the block parameters align with the loop's binding set.
lower_while Updates: The exit block now correctly uses block parameters, fixing a prior bug. The new approach properly routes else_args in the header's Branch terminator, preserving loop-carried SSA through early exit paths.
SemanticStmt::Break and Continue: Both terms gather current SSA values for bindings, emitting a Jump terminator to respective targets (exit_id or header_id), effectively closing the block.
Adjusting lower_stmt: Now incorporates loop_ctx to handle nested control flow scenarios accurately. It fixes a critical issue where break within nested if statements didn’t resolve to the loop’s exit.
Error Handling: Constructs outside loops return UnsupportedSemanticConstruct, and missing SSA bindings throw InternalInvariantViolation.
Refactoring Tests: Existing tests got redirected from Loop to For, setting stage for upcoming improvements.

The structured break/continue commitment aligns with the roadmap, excluding labeled breaks for now—a post-0.1 concern.

Shaping the Agent Operating Doctrine

Commit 03d2da6 introduces substantial documentation with AGENT_OPERATING_DOCTRINE.md, mapping out a six-phase workflow: Recon, Design Lock, Predicted Fallout, Implementation, Validation, and Future Phase. It emphasizes "task packets", which streamline logical work units into single prompts. This marks the inaugural formal documentation of such processes, heralding a shift from unwritten norms to standardized protocols.

No Changes in Merge Dynamics

Despite progress, origin/main remains untouched by recent commits, leaving origin/submain with seven unmerged updates. This extends into the sixteenth day. Daily-log branch backlogs exacerbate potential conflicts, particularly involving daily_log/ and updated documents—an escalating concern as more daily logs stack and further diverge submain from main.

Roadmap Modifications

Today's updates prompt edits in docs/frontend/ROADMAP.md. Phase 10's Active section now highlights the addition of loop, break, and continue implementations with notes on LoopContext and exit block parameters. A specific reference to for loops as the pending gap and a brief summary of changes have been added. Versioning remains at v4.8, last set on 2026-03-28, as no major blockers have been resolved yet, including the ongoing error-model complexities.

Next Steps

Moving forward involves consolidating today's technical groundwork and addressing persisting gaps:

For Loop Lowering: Targeting for loop support, positioning it as a high-priority gap in Phase 10 efforts.
Merging submain: The unmerged backlog grows riskier with each day. Immediate focus is needed to sync submain and main.
Result Lowering Implementation: Placeholder arms for Result need operational wiring within the IR, pressing toward a finished error model.
Clearing Daily-log Backlogs: Prioritize older branches to contain conflict scenarios effectively, maintaining project integrity.

Completion of for loop handling could finish Phase 10, but the error model remains untouched. Clearing merge debts is critical—today’s advancements are steps forward, but the broader structural challenges linger.

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