exams.forge
In exams.forge: Support for Compiling Examination Tasks using the 'exams' Package

knitr::opts_chunk$set(echo = TRUE)

Note: Part the text is taken from the Moodle website, the exams package and the R/exams web site. From my point of view there is no need to reinvent the wheel (or text).

Moodle is a learning platform designed to provide educators, administrators and learners with a single robust, secure and integrated system to create personalised learning environments. Part of Moodle is an activity Quiz which allows a the teacher to design and set quizzes consisting of a large variety of Question types. The questions are stored in a Question bank and can be reused in different quizzes.

The exams package in R allows the automatic generation of exams based on exercises in Markdown or LaTeX format, possibly including R code for dynamic generation of exercise elements. Exercise types include single-choice and multiple-choice questions, arithmetic problems, string questions, and combinations thereof (cloze). Output formats include standalone files (PDF, HTML, Docx, ODT, ...), Moodle XML, QTI 1.2, QTI 2.1, Blackboard, Canvas, OpenOLAT, ARSnova, and TCExam.

Due to Corona I, as statistics teacher, was forced to create online exams. It was a natural way for me to create exercises with R Sweave (or R Markdown) for the Question bank in Moodle. But an online exam is in various ways different to a written exam. Since I'am more familiar with R then with Moodle I decided to create with the exams package dynamic questions, create n replicates using different numbers and upload the questions into Moodle.

To create exercises I use several steps:

exams2pdf(exercisename, nsamp=10) to create one PDF file to check for possible problems in the questions or solutions,
stress_test(exercisename) to see if any problems appear with the questions and to get an idea of the distribution of the correct answers, and
exams.forge(exercisename, n=10) to create a Moodle XML file, here with ten replications.

The difference of using either n or nsamp are of practical nature:

In exams2pdf using n=10 creates ten PDF files, one for each question, whereas nsamp=10 creates one PDF file with all questions.
In exams.forge using n=10 creates one category with ten questions, whereas nsamp=10 creates ten categories containing one question. Whenever you have to delete categories and questions in the question bank in Moodle then you will note the difference :)

Question types

The exams package supports the following answer types for a question:

| exams | Moodle | |----------------------|-----------------| | mchoice | Multiple choice (multiple answers possible) | | schoice | Multiple choice (only one answer possible) | | num | Numerical | | string | Short Answer | | essay | Essay | | cloze | Embedded Answers (Cloze Test / Gap Fill) |

Other Moodle answer types are not (yet?) supported:

Calculated ...
Drag and drop ...
Description
(Random short-answer) Matching
Select missing words

Other could be emulated:

True/False (cloze and schoice)

Essay

%% \extype{string}
%% \exsolution{nil}
%% \exextra[essay,logical]{TRUE}
%% \exextra[essay_format,character]{editor}
%% \exextra[essay_required,logical]{FALSE}
%% \exextra[essay_fieldlines,numeric]{5}
%% \exextra[essay_attachments,numeric]{1}
%% \exextra[essay_attachmentsrequired,logical]{FALSE}
%% \exmaxchars{1000, 10, 50}

Frequently asked questions

How can I force a block of LaTeX to become an image in Moodle?

Source: https://stackoverflow.com/questions/62222053/different-copies-of-question-with-table-for-moodle-with-r-exams

Use the command tex2image from the exams package:

<<echo=FALSE, results=hide>>=
tab <- '\\begin{tabular}{lrr}
\\hline
Name & Min & Max \\\\
\\hline
Foo  & 0   & 1   \\\\
Bar  & 0   & 100 \\\\
\\hline
\\end{tabular}'
tex2image(tab, name = "tab", dir = ".", pt = 8, resize = 250)
@
\includegraphics{tab.png}

Exercise types in `exams` and `Moodle`

library("exams")
exerdir   <- paste0(system.file(package="exams"), "/exercises")
exerfiles <- list.files(path=exerdir, pattern="*.Rnw$")
extype    <- rep('', length(exerfiles))
for (i in seq(exerfiles)) {
  fcont     <- readLines(paste0(exerdir, '/', exerfiles[i]))
  extype[i] <- fcont[grepl("\\extype", fcont, fixed=TRUE)]
}
extype <- gsub('[ \\{\\}%]', '', extype)
extype <- gsub('extype', '', extype, fixed=TRUE)
#
tdir <- tempdir(TRUE)
res  <- exams.forge(exerfiles, n=1, edir=exerdir, tdir=tdir, 
                     name='rexams', schoice = list(eval = exams_eval(rule = "none")))
library("XML")
xmlfile <- xmlParse("rexams.xml")
xmltop  <- xmlRoot(xmlfile)
xmlquestion <- xmlSApply(xmltop, xmlAttrs)
xmlquestion <- xmlquestion[xmlquestion!='category']
#
df <- data.frame(Example_exercise          = sapply(res[[1]], function(e) { e$metainfo$file}),
                 Exercise_type = extype,
                 Cloze_type    = sapply(res[[1]], function(e) { if (is.null(e$metainfo$clozetype)) return('');
                                                               return(paste0(e$metainfo$clozetype, collapse="|"))}),
                 Moodle_type   = xmlquestion,
                 stringsAsFactors = FALSE)
row.names(df) <- NULL
df <- df[order(df$Exercise_type, df$Moodle_type),]
library("knitr")
kable(df, row.names=FALSE)