Source Comparison, Compare/Merge, and Version Control

Complete maintained core interface

The current io1/srccom.lisp contains 26 top-level function definitions. The grouping below is descriptive; every function name in that file is included.

SOURCE-COMPARE is explicitly exported. Its complete configurable surface in the inspected file is:

The maintained FILE structure has six declared fields: cached length, name, type, stream, major mode, and comparison kind. The remaining top-level variables are internal output/merge state: *OUTPUT-STREAM*, *MERGE-LINE-NO*, *RECORD-MERGE-BOUNDS-P*, *MERGE-RECORD*, and *MERGE-THIS-RECORD*.

Form comparison exists in the implementation, but QUERY-TYPE always returns :TEXT; the source comments say the other mode was not useful enough to justify the question. In form mode the code disables labels, requires one matching form, prints no trailing match, reads with READ, and pretty-prints forms. This source-visible path must not be advertised as a normal interactive choice.

SOURCE-COMPARE-FILES returns true when the sources are identical in this maintained LM-3 file. That differs from Genera, whose same-named routine returns true when it encountered any difference.

One static defect reinforces the lineage warning. In current .44, PROMPTED-SOURCE-COMPARE appears to pass its comparison type in the output-stream position. This is a finding about the maintained text, not proof that a loaded System 303 function behaves that way. It remains a runtime TODO.

LM-3 editor integration

The maintained Dired mode binds ordinary = to COM-DIRED-SRCCOM, which rejects directories and entries marked deleted and compares the selected pathname with its highest version. The source also binds a second literal Lisp-machine character, stored as source byte 0x1e, to COM-DIRED-SRCCOM-FILE; that command prompts for an arbitrary second pathname. The mouse menu includes Compare, and Dired typeout pathnames expose a Compare operation. Output goes to a buffer named from the two pathnames.

The same maintained file implements SOURCE-COMPARE-MERGE: it opens an editor on a merge request, builds annotated alternatives through SRCCOM, asks which alternatives to retain, and writes the selected result to the requested output pathname. It is a destructive writer and was not exercised here.

Later zwei/patch/zwei-126-* files contain Source Compare, Source Compare Changes, and merge commands. They are patch-line evidence, not a safe basis for claiming that those named commands are installed in the untouched System 303 world. The current unpatched zwei/zmacs.lisp does not itself define those commands.

No CADR screenshot is published for this dossier. A useful runtime test requires two synthetic files on a disposable private CADR disk plus proof of the actual loaded SRCCOM function identity; that remains a TODO rather than being inferred from the maintained tree.

Complete core interface and drift

Genera's licensed io1/srccom.lisp contains 22 live top-level functions; the block-commented compatibility macro is excluded.

The FILE structure adds a buffer-pointer table, an EOF flag, and presentation type and object slots. Output can therefore make file pathnames, buffers, and line locations presentation-sensitive instead of emitting only inert prose.

The complete set of live top-level variables in this Genera file is *OUTPUT-STREAM*, *PRINT-LABELS*, *SRRCOM-LINE-COMPARISON-FUNCTION*, *SRRCOM-STRING-COMPARISON-FUNCTION*, *PATHNAME-DEFAULTS*, *DIFFERENCE-PRINTER*, *LINES-NEEDED-TO-MATCH*, *LINES-TO-PRINT-BEFORE*, *LINES-TO-PRINT-AFTER*, *MERGE-LINE-NO*, *RECORD-MERGE-BOUNDS-P*, *MERGE-RECORD*, and *MERGE-THIS-RECORD*.

SOURCE-COMPARE accepts two filenames, optional output stream and PRINT-COMMENTS, plus these keywords:

The source contains a TODO for ignoring comments; it does not implement that option. An old multi-font/Japanese decoding wrapper is under an inactive conditional, so it is not counted as live behavior. The two dynamically bound comparison variables are spelled *SRRCOM-LINE-COMPARISON-FUNCTION* and *SRRCOM-STRING-COMPARISON-FUNCTION* in the preserved source; the doubled R is retained here because it is part of the interface text.

The main loop returns ANY-DIFFERENCES: false means equal and true means at least one mismatch. This is the reverse of the maintained LM-3 return convention. Code ported between the two environments cannot safely treat the result as a stable “equal” predicate.

Complete Zmacs named-command surface

All eight base commands below are installed in the Zmacs named-command table. No fixed direct key is assigned by the base Zmacs table; invoke them through Meta-X, menus, or a user binding.

For each operand, the general commands offer exactly these choices:

The numeric argument is decoded by bits, not magnitude ranges: bit 2 ignores case and style, bit 4 ignores leading whitespace, and 6 requests both. A Source Compare buffer is reusable for the same pair in either order; its specialized revert method clears the typeout-derived contents.

Merge conflict controls

The first prompt for each conflict accepts the complete set below.

After !, the allowed policies are first, second, both, indicators, or Rubout to leave the policy question. A tentative 1, 2, or * choice reaches a second prompt: Space confirms, Rubout restores the prior text, Control-R edits, and Help explains the confirmation stage.

The public Genera 8 editing manual says the first and second merge questions also have a mouse interface. The later 8.5 source explicitly says the mouse path had been broken since Release 4 and removes its remnants. For this preserved source, the keyboard interface above is the high-confidence claim; the manual's mouse statement is retained as historical documentation, not current behavior.

Dired, changed-file queries, and window comparison

Genera Dired binds = to compare the selected version with newest. A numeric argument prompts for the second pathname; the same 2/4 option bits apply. A pathname presentation also exposes Compare. Unlike maintained LM-3 Dired, the Genera wrapper passes DELETED T through to SRCCOM.

When Zmacs discovers that an unedited visited file changed on disk, its revert query offers Yes, No, and Compare. Choosing Compare opens an accepting-values form with exactly two booleans: Ignore Case and Style and Ignore Leading Whitespace. The comparison does not itself choose whether to revert.

Compare Windows is a separate editor command, not SRCCOM. Starting at point in two selected windows, it compares characters until the first difference and moves both points there. With more than two windows, decimal digits of a numeric argument identify the two window positions. It produces locations, not an annotated diff or merge buffer.

Complete source-visible editor command surface

Test Merge Environment is a source-visible debugging minor-mode initializer, not counted as a normal user command. An older diagram-oriented interface and commands named Resolve Differences, Remove Comparison Header, and Remove Compare Diagrams are inside a block comment and are not counted as live current UI.

The merge-acceleration mode installs these controls:

Compare Merge Multiple Files opens an accepting-values form whose complete source-visible controls are:

• Enable automatic merging and Type out differences on the typeout window;
• a repeatable source sequence, each choosing Pathname or Zwei Buffer and then the object;
• when automatic merging is enabled, source option None, Original, Old Original, or Force Edit;
• result disposition Pathname, Special Buffer, Overwrite, or, when no wildcard pathname is present, Buffer;
• a target pathname or target buffer when that disposition needs one.

Wildcard source sets are paired by name and type. The source rejects mixing a Zmacs buffer with wildcard pathname sets. A source-only anomaly is that the local EDIT-DIFFERENCES-P variable is returned to the caller but no accepting-values control assigns it in the preserved text, so automatic entry into difference editing is not claimed without a compiled/runtime check.

The evacuated Lisp source retains Symbolics 006 edit records, and its raw form has unmatched parentheses if those histories are treated as ordinary text. This dossier reports the greatest logical source revision and identifies edit alternatives; it does not claim that loading the raw evacuated file is a valid reconstruction method.

Complete active editor implementation inventory

There are 25 active source-visible editor command implementations: 24 live DEFCOM forms in commands.lisp, plus the contextual COM-VC-MENU in diagram-lines.lisp. The sole additional textual DEFCOM, Show VC Section Data, is block-commented and excluded.

The VC file-buffer minor mode installs four fixed controls:

Its named menu contains 17 labels: Set Buffer Disposition, Split Hard Section, Kill Hard Section, Show Modification Comments, Hide Modification Comments, Show VC Section Data, Merge VC File Branches, Show VC File Branches, Show Section History, Show Section Authors, List Modified Sections, Show Section Changes, Show All Section Changes, Show Branch Lock Status, Break Branch Lock, Revert Section, and List Deleted Sections.

That menu exposes a source defect: Show VC Section Data remains in the menu, but its only definition is inside a block comment. Invoking it from a source-equivalent build would target an undefined command unless another patch supplied it.

The current implementation also makes a hard-section title presentation-sensitive: Middle kills an existing section, while Super-Mouse-Left opens the contextual menu. The source's named menu is richer than the November 1987 guide's command list.

Complete Command Processor inventory

The declared vc-interfaces source contains 16 Command Processor definitions. Many create, rewrite, extract, delete, or lock files; none was executed in this museum run.

The guide's CP summary names Show VC File Versions, while the current source registers Show VC File Branches. The guide also documents UnKill Hard Section, but no live definition occurs anywhere in the inspected media source. Conversely, current source adds Section Authors, Deleted Sections, Revert Section, system-wide section changes, and the contextual menu beyond the guide's summary. These are version differences, not synonyms silently normalized by this page.

Package interface

VERSION-CONTROL (VC) has no export list; its source comment says an export plan had not been chosen. VERSION-CONTROL-INTERNALS (VCI) exports 85 symbols. Six names begin with raw Lisp-machine character byte 0x8d; the portable transcription [LM-char-215] below records the byte's octal value without guessing a Unicode identity.

The verified total is 85 unique source symbols.