Merging

This section is a brief introduction to Merging as used with Configuring. For a more detailed description, see Chapter 13, Starting Merging and Loading Files."

Merging Window

Merging displays two text files (the parent and child deltas) for side-by-side comparison, each in a read-only pane (see Figure 4-1). Beneath them is a pane that contains a merged version of the two files. The merged version contains selected lines from either or both deltas and can be edited to produce a final merged version.

Each delta in each of the top panes is shown in comparison to the common ancestor delta:

• The child delta is displayed in the left pane labeled Child

• The parent delta is displayed in the right pane labeled Parent

The common ancestor is the delta from which both the parent and child deltas are descended. This arrangement permits you to make a three-way comparison--each delta to the common ancestor, and each delta to the other.

Marking of Differences

Lines in each descendant are marked according to their relationship to the corresponding lines in the common ancestor:

• If a line is identical in all three deltas, then no glyph appears.

• If a line is not in the ancestor but was added to one or both of the descendants, then a plus sign glyph (+) appears next to the line in the delta where the line was added.

• If a line is present in the ancestor but was removed from one or both of the descendants, then a minus sign (-) appears as a placeholder in the delta from which the line was removed.

• If a line is in the ancestor but has been changed in one or both of the descendants, then a vertical bar glyph (|) appears next to the line in the delta where the line was changed.

When Merging discovers a line that differs between either of the two deltas and the ancestor, it marks with glyphs the lines in the two deltas and also in the automatically merged file. Together, these marked lines are called a difference. While Merging is focusing on a difference, it highlights the glyphs.

The difference on which Merging is focusing at any given time is called the current difference. The difference that appears immediately later in the file is called the next difference; the difference that appears immediately earlier in the file is called the previous difference.

Resolving Differences

While focusing on a difference, you can accept a line from either of the original deltas, or you can edit the merged version by hand. When you indicate that you are satisfied with your changes (by clicking on a control panel button), the current difference is said to be resolved. After a difference is resolved, Merging changes the glyphs that mark the difference to outline (hollow) font. Merging then automatically advances to the next difference (if the Auto Advance property is on), or moves to another difference of your choice.