demos: add a --fast mode to speed up recording

It can take quite a while to record a demo. This patch adds a `--fast`
flag for reducing delays to a tenth of the usual. You can play the
recording with `asciinema play -s 0.1` to get close-to-normal speed
(except that command delays will be slower). That way you can adjust
timings with shorter round-trips.

demos/demo_git_compat.sh

@@ -9,13 +9,13 @@ run_demo 'Clone a Git repo' '
 run_command "# Clone a Git repo:"
 run_command "jj git clone https://github.com/octocat/Hello-World"
 run_command "cd Hello-World"
-sleep 1
+pause 1
 run_command "# Inspect it:"
-sleep 1
+pause 1
 run_command "jj log"
-sleep 5
+pause 5
 run_command "jj diff -r b1"
-sleep 2
+pause 2
 run_command "# The repo is backed by the actual Git repo:"
 run_command "git --git-dir=.jj/store/git log --graph --all --decorate --oneline"
 '

demos/demo_helpers.sh

@@ -5,6 +5,7 @@ BASE_DIR=$(realpath "$(dirname "$0")")
 UPLOAD=false
 PREVIEW=false
 DEBUG=false
+FAST=false
 parse_args() {
     for arg in "$@"; do
         case "$arg" in
@@ -27,6 +28,9 @@ Arguments:
         --debug)
             DEBUG=true
             ;;
+        --fast)
+            FAST=true
+            ;;
         *)
             echo "Unrecognized argument: $arg"
             exit 1
@@ -46,7 +50,16 @@ new_tmp_dir() {
 run_demo() {
     local title="$1"
     local test_script="$2"
+    local fast=""
+    if [[ "$FAST" == true ]]; then
+      fast="set send_human {0.005 0.01 1 0.005 0.1}
+proc pause {duration} {
+    sleep [expr \$duration / 10.0]
+}
+"
+    fi
     local expect_script="source $BASE_DIR/demo_helpers.tcl
+$fast
 spawn asciinema rec -c \"PS1='$ ' bash --norc\" --title \"$title\"
 expect_prompt
 $test_script

demos/demo_helpers.tcl

@@ -1,6 +1,10 @@
 set send_human {0.05 0.1 1 0.05 1}
 set timeout 2
 
+proc pause {duration} {
+    sleep $duration
+}
+
 proc expect_prompt {} {
     expect "$ "
 }

demos/demo_operation_log.sh

@@ -11,26 +11,26 @@ run_demo 'The entire repo is under version control' '
 run_command "# We are in the octocat/Hello-World repo."
 run_command "# The \"operation log\" shows the operations so far:"
 run_command "jj op log"
-sleep 7
+pause 7
 run_command "# We are going to make some changes so we can see how the operation log works."
 run_command "# We are currently working off of the \"master\" branch:"
 run_command "jj log"
-sleep 5
+pause 5
 run_command "# Let'\''s add a file, set a description, and rebase onto the \"test\" branch:"
 run_command "echo stuff > new-file"
-sleep 2
+pause 2
 run_command "jj describe -m stuff"
-sleep 2
+pause 2
 run_command "jj rebase -d test"
-sleep 2
+pause 2
 run_command "# We are now going to make another change off of master:"
 run_command "jj co master"
-sleep 1
+pause 1
 run_command "jj describe -m \"other stuff\""
-sleep 2
+pause 2
 run_command "# The repo now looks like this:"
 run_command "jj log"
-sleep 5
+pause 5
 run_command "# And the operation log looks like this:"
 send -h "jj op log\r"
 # Capture the third latest operation id (skipping color codes around it)
@@ -38,19 +38,19 @@ expect -re "o ..34m(.*?)..0m "
 expect -re "o ..34m(.*?)..0m "
 set rebase_op $expect_out(1,string)
 expect_prompt
-sleep 7
+pause 7
 run_command "# Let'\''s undo that rebase operation:"
 run_command "jj undo -o $rebase_op"
-sleep 3
+pause 3
 run_command "# The \"stuff\" change is now back on master as expected:"
 run_command "jj log"
-sleep 5
+pause 5
 run_command "# We can also see what the repo looked like after the rebase operation:"
 run_command "jj --at-op $rebase_op log"
-sleep 5
+pause 5
 run_command "# Looks nice, let'\''s go back to that point:"
 run_command "jj op restore -o $rebase_op"
-sleep 2
+pause 2
 run_command "# We'\''re now back to before the \"other stuff\" change existed:"
 run_command "jj log"
 '

demos/demo_working_copy.sh

@@ -11,34 +11,34 @@ run_demo 'The working copy is automatically committed' '
 run_command "# We are in the octocat/Hello-World repo."
 run_command "# We have an empty working copy on top of master:"
 run_command "jj log"
-sleep 5
+pause 5
 run_command "jj status"
-sleep 2
+pause 2
 run_command "# Now make some changes in the working copy:"
 run_command "echo \"Goodbye World!\" > README"
 run_command "echo stuff > new-file"
 run_command "# Our working copy commit id changed because we made changes:"
 run_command "jj status"
-sleep 5
+pause 5
 run_command "# Add a branch so we can easily refer to this commit:"
 run_command "jj branch goodbye"
-sleep 2
+pause 2
 run_command "# Start working on a new change off of master:"
 run_command "jj co master"
-sleep 2
+pause 2
 run_command "# Note that the working copy is now clean; the \"goodbye\" change stayed in its own commit:"
 run_command "jj status"
-sleep 5
+pause 5
 run_command "# Modify a file in this new change:"
 run_command "echo \"Hello everyone!\" > README"
-sleep 2
+pause 2
 run_command "# The working copy is not special; we can, for example, set the description of any commit."
 run_command "# First, set it on the working copy:"
 run_command "jj describe -m everyone"
-sleep 2
+pause 2
 run_command "# Now set it on the change we worked on before:"
 run_command "jj describe goodbye -m goodbye"
-sleep 2
+pause 2
 run_command "# Inspect the result:"
 run_command "jj log"
 '