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Type and Run R Code with Live Evaluation

Source: R/typeRun.R
typeRun.Rd

An enhanced version of typeR that not only simulates typing but also evaluates R code in real-time. Supports interactive pause/resume control and handles both Quarto/R Markdown documents and plain R scripts.

Usage

typeRun(
  file,
  delay = 0.05,
  jitter = 0.01,
  max_print = 10,
  envir = new.env(parent = .GlobalEnv)
)

Arguments

file

Character string. Path to an R script (.R), R Markdown (.Rmd), or Quarto (.qmd) file to type and execute.

delay

Numeric. Base delay in seconds between typing each character. Default is 0.05 (50 milliseconds).

jitter

Numeric. Standard deviation for random variation in typing speed, adding natural typing rhythm. Default is 0.01.

max_print

Integer. Maximum number of elements to print for long outputs (vectors, data frames, matrices, lists). Default is 10.

envir

Environment. The environment in which to evaluate R code. Default is a new environment with the global environment as parent.

Value

Invisibly returns NULL. Called for side effects (typing animation and code evaluation).

Details

typeRun() extends the basic typeR() functionality by:

  • Live Code Evaluation: Executes R code chunks as they are typed

  • Interactive Control: Press ESC/Ctrl+C to pause, then choose to resume or stop

  • Smart Output: Truncates long outputs and handles models intelligently

  • Format Support: Handles .R, .Rmd, and .qmd files intelligently

For Quarto/R Markdown files, typeRun():

  • Skips YAML headers

  • Only evaluates code in R code chunks

  • Preserves narrative text without evaluation

For R scripts, it evaluates all non-comment, non-empty lines.

Output Handling

  • Assignments and plotting functions execute silently

  • Long vectors/data frames are truncated to max_print elements

  • Model summaries (lm, glm, etc.) display using R's standard print methods

  • Raw model objects (without summary call) show a simple fitted message

  • Package loading messages (library/require) are suppressed

  • Errors are caught and displayed without stopping execution

Interactive Control

During execution, you can:

  1. Press ESC (or Ctrl+C on some systems) to pause

  2. Enter 1 to resume from where you paused

  3. Enter 2 to stop completely

See also

typeR for typing without evaluation

Examples

if (FALSE) { # \dontrun{
# Type and run a simple R script
typeRun("analysis.R")

# Type and run with slower, more dramatic effect
typeRun("demo.R", delay = 0.1, jitter = 0.02)

# Type and run a Quarto document with limited output
typeRun("report.qmd", max_print = 5)

# Use a specific environment for evaluation
my_env <- new.env()
typeRun("script.R", envir = my_env)
ls(my_env)  # See what was created

# Create a demo file and run it
cat("# Simple Demo\nx <- 1:10\nmean(x)\nplot(x)\n", file = "demo.R")
typeRun("demo.R")
} # }