Drafting Commands, Metaediting Part II: The Core Commands - - PowerPoint PPT Presentation

Lecture 8: Visual Mode, /<CR>, Drafting Commands, Metaediting

Part II: The Core Commands

Announcements

• HW3... is postponed to next week...

– Too few things to test on – Make sure to practice on commands discussed so far. Every single command in this course is important! (Each has an equal chance of showing up on the exams)

Last Time

• Text Objects!
• Motions....

Last Time

• Text Objects!
• Motions....
• Today: Visual Mode!

Reminder...

• As always, in regular text editing, there

is a certain order that we tend to prioritize: 1.Text objects: views objects as fundamental elements of text

• 1. word/WORD objects
• 2. line objects
• 3. enclosed objects

Reminder...

• As always, in regular text editing, there

is a certain order that we tend to prioritize:

• 2. Motions: deals with "chunks of text"

that cannot be expressed by simply stating what objects they are.

Reminder...

• As always, in regular text editing, there

is a certain order that we tend to prioritize:

• 2. Motions: deals with "chunks of text"

that cannot be expressed by simply stating what objects they are.

– Usually complicated combinations of

• bjects.

– Are straightforward, and uninteresting.

Reminder...

• As always, in regular text editing, there

is a certain order that we tend to prioritize:

• 2. Motions: deals with "chunks of text"

that cannot be expressed by simply stating what objects they are.

– What could possibly go wrong?

• Visual Mode
• 1 Character Editing Commands and

Drafting Commands

• /<pattern><CR> and Metaediting.

• Visual Mode
• 1 Character Editing Commands and

Drafting Commands

• /<pattern><CR> and Metaediting.

Issues with Motions

Issues with Motions

Task: Change to "in C, we can use ``variableinstance.function'' to access its member variables."

Issues with Motions

Task: Change to "in C, we can use ``variableinstance.function'' to access its member variables." Well?

Issues with Motions

Task: Change to "in C, we can use ``variableinstance.function'' to access its member variables." Well? Obvious Solution: c/.<CR>yaddayadda<Esc>

Issues with Motions

Task: Change to "in C, we can use ``variableinstance.function'' to access its member variables." Well? Obvious Solution: c/.<CR>yaddayadda<Esc>

Nonobvious Result: ...

Issues with Motions

• The gotcha:

c<object>

• Command deals with only ONE object or

ONE motion!

Issues with Motions

• The gotcha:

c<object>

• Command deals with only ONE object or

ONE motion!

• How do we deal with complicated

descriptions? (relative, cheating, etc...)

In the good ol' days of vi...

In the good ol' days of vi...

In the good ol' days of vi...

Can't do that...

In the good ol' days of vi...

Can't do that...

(workaround: marks, regex tricks, more accurate regex matching)

In the good ol' days of vi...

Today: Vim

Editing Commands follow the format: <command><object/motion>

Today: Vim

Editing Commands follow the format: <command><object/motion>

Issue: how do we know that

• ur description has ended?

Possible Workarounds

• Some kind of termination signal to tell

Vim that we have finished our description...

– Very Problematic: no longer vi-compatible, extra keystrokes for EVERY single edit command, too many commands (keyboard fully mapped)

Possible Workarounds

• Some kind of termination signal to tell

Vim that we have finished our description...

– Very Problematic: no longer vi-compatible, extra keystrokes for EVERY single edit command, too many commands (keyboard fully mapped)

• What Vim actually does: Visual Mode!

Visual Mode: The Idea

• Nearly all Vim commands have a clear

seperation of editing process:

• 1. Locate
• 2. Edit
• 3. (Repeat)
• These commands are hence disjoint!

Visual Mode: The Idea

• Instead of structuring our commands

like this: <command><object/motion>

• We do this:

<object/motion><command>

Visual Mode: The Idea

• Instead of structuring our commands

like this: <command><object/motion>

• We do this:

<object/motion><command>

• How do we know that our motion has

terminated?

Visual Mode: The Idea

• Instead of structuring our commands like

this: <command><object/motion>

• We do this:

<object/motion><command>

• How do we know that our motion has

terminated? When we reach an edit command!

Visual Mode

• Three kinds, with radically different

use cases:

– Visual Mode (today) – Visual Line Mode – Visual Block Mode

Visual Mode

• Three kinds, with radically different

use cases:

– Visual Mode (today)

• to allow complicated descriptions for locates

– Visual Line Mode

• to allow "chuck" execution of ex commands or

normal mode commands

– Visual Block Mode

• practically useless... very few contrived use

cases.

Visual Mode

• Descriptions are highlighted.
• Enter/Exit with the v command.
• Demo.
• Use case: nearly always paired with use
• f f and t commands! Deals with any

kind of code that is even slightly complicated.

Visual Mode

• Commands:
• Nearly all normal mode commands work

as expected, only in reverse order: v<object/motion><command>

• v - enter/escape visual mode
• V, <C-v> - switch to visual line/block

mode

Visual Mode

• Commands:
• gv - reselect previous selection

– VERY useful for redoing typos

• o - go to the other end of the selection

– Used in combination with gv for convenient continuting navigation.

Visual Mode

• Commands:
• gv - reselect previous selection

– VERY useful for redoing typos

• Hm.... How does gv work?

– where and how is previous selection stored? – what happens if we perform edits?

Visual Mode

• Commands:
• gv - reselect previous selection

– VERY useful for redoing typos

• Hm.... How does gv work?

– where and how is previous selection stored? – what happens if we perform edits?

• Will be addressed in HW 3!

• Visual Mode
• 1 Character Editing Commands and

Drafting Commands

• /<pattern><CR> and Metaediting.

Miscellaneous: 1-Character Commands

• ... are used nearly exclusively to fix one

character typos.

• Used surprisingly frequently: one

character typos happen often.

• Optimized keystrokes.
• Fixed Pattern:

/<line><CR>f<char><1-char-edit>

Miscellaneous: 1-Character Commands

• Commands:
• r<char> - replace character with <char>
• x - delete character
• s - change character (go to insert mode)
• vU/vu - trick to capitalize/lowercase one

character.

• J - command to trim end of line and join two

lines together. (not quite 1 character)

Drafting Commands

• Drafting: appending/inserting huge

chuncks of text.

Drafting Commands

• Drafting: appending/inserting huge

chuncks of text.

• Not much involved, remember a few

very common use case patterns:

Drafting Commands

• Base Commands:
• i - insert in front of cursor
• a - append at end of cursor
• I - insert in front of line
• A - append at end of cursor

Drafting Commands

• VERY Common Patterns:
• /<line><CR>I/A: insert in front
• f/append at end of line containing

<line>.

• /<word><CR>i: insert in front of <word>
• /<word><CR>ea: append at end of

<word>

• /<line><CR>f<char>i/a: insert in front
• f/append at end of <char> from <line>

Speaking of Which...

• The /<pattern><CR> command...
• ... is THE MOST IMPORTANT command

in Vim!

Speaking of Which...

• The /<pattern><CR> command...
• ... is THE MOST IMPORTANT command

in Vim!

• Which we will devote the rest of

today's lecture to!

• Visual Mode
• 1 Character Editing Commands and

Drafting Commands

• /<pattern><CR> and Metaediting.

/<pattern><CR> ... again!

• ... is very very versatile!

/<pattern><CR> ... again!

• ... is very very versatile!
• But first, what's a <pattern>?

vimregex

• a <pattern> is a form of vim regular

expression.

vimregex

• a <pattern> is a form of vim regular

expression.

• Depressing fact of life: vim has 4

different flavors of regular expressions!

vimregex

• a <pattern> is a form of vim regular

expression.

• Depressing fact of life: vim has 4

different flavors of regular expressions!

– NONE of which is EQUIVALENT to regular expressions of programming languages. – Only SIMILAR, which means that you'll still have to "relearn" it.

vimregex

• 4 flavors:
• verynomagic
• nomagic
• magic
• verymagic
• ... Each with their own rules!
• ... and extremely questionable reasons

for having 4 different standards...

vimregex

• 4 flavors:
• verynomagic
• nomagic
• magic
• verymagic
• ... Each with their own rules!
• ... and extremely questionable reasons

for having 4 different standards...

vimregex

• Good news: you don't have to know any

particular flavor! (I can't memorize it all either).

• Onwards, we will use the 'magic' regex

syntax:

– put this in vimrc:

• set magic

vimregex

• Bottom Line:

– Vim has 4 flavors of regex. – Each regex has its own conventions. – Used for pattern matching. – vimregex is NOT regular! There are capture groups.

vimregex

• So what can we do?

vimregex

• So what can we do?
• Useful facts:
• . - matches any character.

vimregex

• So what can we do?
• Useful facts:
• . - matches any character.
• Very useful for matching characters

that are annoying to type (\n) or have bad ergonomics (&) etc...

vimregex

• So what can we do?
• Useful facts:
• . - matches any character.
• * - matches any number of previous

group.

vimregex

• So what can we do?
• Useful facts:
• . - matches any character.
• * - matches any number of previous

group.

• .* - matches any phrase that you

REALLY don't wanna type.

Back to /<pattern><CR>

• Like many commands in Vim, it can

either be a forward direction or a reverse direction.

Back to /<pattern><CR>

• Like many commands in Vim, it can

either be a forward direction or a reverse direction. /<pattern><CR>

• Matches next pattern

?<pattern><CR>

• Matches previous pattern

Is there more to /pattern<CR>?

• Yes! But first, the interface...

Command Line Interface

• The /<pattern><CR> command has

"nearly" the exact same interface as typing out ex commands.

• Properties:

– One Line – Insert Mode Commands – History Recall

Command Line Interface

• The /<pattern><CR> command has "nearly" the exact

same interface as typing out ex commands.

• Commands:
• <C-n> - unix standard for next search history
• <C-p> - unix standard for previous search history
• <C-w> - unix standard for delete word (but follows

Vim's definition of word)

• <C-u> - unix standard for delete line
• <C-r> - insert from register

Command Line Interface

• Commands:
• Important:
• <C-r><C-w> - insert word under cursor!
• <C-r><C-a> - insert WORD under

cursor!

• Exceedingly useful! Saves a lot of

typing.

Command Line Interface

• Commands:
• Important:
• <C-r><C-w> - insert word under cursor!
• <C-r><C-a> - insert WORD under

cursor!

• Exceedingly useful! Saves a lot of

typing.

• Can we do that from normal mode as

well? YES!

Command Line Interface

• Commands:
• In normal mode:
• * - searches word under cursor
• # - reverse searches word under cursor
• Saves going into command line

altogether!

Command Line Interface

• But, is there EVEN MORE?

Command Line Interface

• But, is there EVEN MORE?

Command Line Interface

• But, is there EVEN MORE?
• It'll be sad if everything just ends here...
• We would expect that if we made a

mistake in the command line interface, we should have equal power to fix it..

– same tools: locate, edit, repeat, etc...

Command Line Interface

• First, a detour:
• Where, and how, does Vim stores its

search history?

Command Line Interface

• First, a detour:
• Where, and how, does Vim stores its

search history?

– .viminfo file – loaded into a specialized memory segment.

Command Line Interface

• First, a detour:
• Where, and how, does Vim stores its

search history?

– .viminfo file – loaded into a specialized memory segment.

Command Line Interface

• First, a detour:
• Where, and how, does Vim stores its

search history?

– .viminfo file – loaded into a specialized memory segment.

• What does that mean?

Metaediting

• Since we have stored our previous

searches, there should be a mechanism to quickly perform edits on previous searches for editing. (Hence, metaediting. Editing your edits).

Simple Case: flags

• A more general syntax of search:

/<pattern>/<flags><CR>

• If <pattern> is left blank, automatically

repeats previous search!

Simple Case: flags

• A more general syntax of search:

/<pattern>/<flags><CR>

• If <pattern> is left blank, automatically

repeats previous search!

• Most important <flag>:
• e - places cursor at end of match

Simple Case: flags

• A more general syntax of search:

/<pattern>/<flags><CR>

• If <pattern> is left blank, automatically repeats

previous search!

• Example:
• /hello<CR> - matches "hello"
• //e<CR> - matches "hello" and moves cursor to 'o'
• /<C-r><C-w> there/e - matches "hello" there and moves

cursor to end of the "there".

Even more powerful metaediting!

• Command line history of searches!
• Works exactly as expected (with modes, etc).
• Commands:
• q/ - open command line history
• <C-f> - when typing out pattern, switch to

command line history

• <C-c> - switch back from command line history

to command line.

• demo

Even more powerful metaediting!

• Command line history of searches!
• Works exactly as expected (with modes, etc).
• Commands:
• q/ - open command line history
• <C-f> - when typing out pattern, switch to

command line history

• <C-c> - switch back from command line history

to command line.

• demo

Next Time

• What about registers and macros?
• What can we do with visual line mode and ex

commands?

• There are a ton of commands today! Practice

practice practice.

• All of them are important, put them in finger

memory!