Replace Modes and Insert Mode Completion

============================================================================== 5. Replace mode *Replace* *Replace-mode* *mode-replace* Enter Replace mode with the "R" command in normal mode. In Replace mode, one character in the line is deleted for every character you type. If there is no character to delete (at the end of the line), the typed character is appended (as in Insert mode). Thus the number of characters in a line stays the same until you get to the end of the line. If a <NL> is typed, a line break is inserted and no character is deleted. Be careful with <Tab> characters. If you type a normal printing character in its place, the number of characters is still the same, but the number of columns will become smaller. If you delete characters in Replace mode (with <BS>, CTRL-W, or CTRL-U), what happens is that you delete the changes. The characters that were replaced are restored. If you had typed past the existing text, the characters you added are deleted. This is effectively a character-at-a-time undo. If the 'expandtab' option is on, a <Tab> will replace one character with several spaces. The result of this is that the number of characters in the line increases. Backspacing will delete one space at a time. The original character will be put back for only one space that you backspace over (the last one). ============================================================================== 6. Virtual Replace mode *vreplace-mode* *Virtual-Replace-mode* Enter Virtual Replace mode with the "gR" command in normal mode. Virtual Replace mode is similar to Replace mode, but instead of replacing actual characters in the file, you are replacing screen real estate, so that characters further on in the file never appear to move. So if you type a <Tab> it may replace several normal characters, and if you type a letter on top of a <Tab> it may not replace anything at all, since the <Tab> will still line up to the same place as before. Typing a <NL> still doesn't cause characters later in the file to appear to move. The rest of the current line will be replaced by the <NL> (that is, they are deleted), and replacing continues on the next line. A new line is NOT inserted unless you go past the end of the file. Interesting effects are seen when using CTRL-T and CTRL-D. The characters before the cursor are shifted sideways as normal, but characters later in the line still remain still. CTRL-T will hide some of the old line under the shifted characters, but CTRL-D will reveal them again. As with Replace mode, using <BS> etc will bring back the characters that were replaced. This still works in conjunction with 'smartindent', CTRL-T and CTRL-D, 'expandtab', 'smarttab', 'softtabstop', etc. In 'list' mode, Virtual Replace mode acts as if it was not in 'list' mode, unless "L" is in 'cpoptions'. Note that the only situations for which characters beyond the cursor should appear to move are in List mode |'list'|, and occasionally when 'wrap' is set (and the line changes length to become shorter or wider than the width of the screen). In other cases spaces may be inserted to avoid following characters to move. This mode is very useful for editing <Tab> separated columns in tables, for entering new data while keeping all the columns aligned. ============================================================================== 7. Insert mode completion *ins-completion* In Insert and Replace mode, there are several commands to complete part of a keyword or line that has been typed. This is useful if you are using complicated keywords (e.g., function names with capitals and underscores). Completion can be done for: 1. Whole lines |i_CTRL-X_CTRL-L| 2. keywords in the current file |i_CTRL-X_CTRL-N| 3. keywords in 'dictionary' |i_CTRL-X_CTRL-K| 4. keywords in 'thesaurus', thesaurus-style |i_CTRL-X_CTRL-T| 5. keywords in the current and included files |i_CTRL-X_CTRL-I| 6. tags |i_CTRL-X_CTRL-]| 7. file names

This section explains the standard Replace mode, focusing on how characters are replaced and restored, and the effects of deleting changes. It then introduces Virtual Replace mode, which replaces screen real estate instead of actual characters to prevent movement of characters further in the file, especially useful for editing aligned columns in tables. Finally, it covers Insert mode completion, detailing various commands to complete keywords or lines using sources like the current file, dictionaries, thesauruses, included files, tags, and file names.