use requirements package to find lesson dependencies

diff --git a/bin/generate_md_episodes.R b/bin/generate_md_episodes.R
index 2f4e1f93e063fa5789ce0a3b45a5092b13f85fa3..e2592c22ea4b4e2f3318c08376abfb52f0f2eb77 100644 (file)
--- a/bin/generate_md_episodes.R
+++ b/bin/generate_md_episodes.R
@@ -1,40 +1,44 @@
 generate_md_episodes <- function() {
 
-    library("methods")
-    
-    if (require("knitr") && packageVersion("knitr") < '1.9.19')
-        stop("knitr must be version 1.9.20 or higher")
-
-    if (!require("stringr"))
-        stop("The package stringr is required for generating the lessons.")
-
-    if (require("checkpoint") && packageVersion("checkpoint") >=  '0.4.0') {
-        required_pkgs <-
-             checkpoint:::scanForPackages(project = "_episodes_rmd",
-                                          verbose=FALSE, use.knitr = TRUE)$pkgs
-    } else {
-        stop("The checkpoint package (>= 0.4.0) is required to build the lessons.")
-    }
-
-    missing_pkgs <- required_pkgs[!(required_pkgs %in% rownames(installed.packages()))]
-
-    if (length(missing_pkgs)) {
-        message("Installing missing required packages: ",
-                paste(missing_pkgs, collapse=", "))
-        install.packages(missing_pkgs)
-    }
-
-    ## get the Rmd file to process from the command line, and generate the path for their respective outputs
-    args  <- commandArgs(trailingOnly = TRUE)
-    if (!identical(length(args), 2L)) {
-      stop("input and output file must be passed to the script")
-    }
-    
-    src_rmd <- args[1]
-    dest_md <- args[2]
-
-    ## knit the Rmd into markdown
-    knitr::knit(src_rmd, output = dest_md)
+  library("methods")
+  
+  if (!require("remotes")) {
+    stop("The `remotes` package is needed.")
+  }
+
+  if (!require("requirements")) {
+    remotes::install_github("hadley/requirements")
+  }
+
+  required_pkgs <- unique(c(
+    ## Packages for episodes
+    requirements:::req_dir("_episodes_rmd"),
+    ## Pacakges for tools
+    requirements:::req_dir("bin")
+  ))
+
+  missing_pkgs <- setdiff(required_pkgs, rownames(installed.packages()))
+
+  if (length(missing_pkgs)) {
+    message("Installing missing required packages: ",
+            paste(missing_pkgs, collapse=", "))
+    install.packages(missing_pkgs)
+  }
+
+  if (require("knitr") && packageVersion("knitr") < '1.9.19')
+    stop("knitr must be version 1.9.20 or higher")
+
+  ## get the Rmd file to process from the command line, and generate the path for their respective outputs
+  args  <- commandArgs(trailingOnly = TRUE)
+  if (!identical(length(args), 2L)) {
+    stop("input and output file must be passed to the script")
+  }
+
+  src_rmd <- args[1]
+  dest_md <- args[2]
+
+  ## knit the Rmd into markdown
+  knitr::knit(src_rmd, output = dest_md)
 
     # Read the generated md files and add comments advising not to edit them
     vapply(dest_md, function(y) {
@@ -43,7 +47,7 @@ generate_md_episodes <- function() {
       if (mdfile[1] != "---")
         stop("Input file does not have a valid header")
       mdfile <- append(mdfile, "# Please do not edit this file directly; it is auto generated.", after = 1)
-      mdfile <- append(mdfile, paste("# Instead, please edit", 
+      mdfile <- append(mdfile, paste("# Instead, please edit",
                                      basename(y), "in _episodes_rmd/"), after = 2)
       writeLines(mdfile, con)
       close(con)