fix(tools): address faulty CRAN mirrors and lint issues

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
report:
  - task: lint_filenames
    status: passed
  - task: lint_editorconfig
    status: passed
  - task: lint_markdown
    status: na
  - task: lint_package_json
    status: na
  - task: lint_repl_help
    status: na
  - task: lint_javascript_src
    status: na
  - task: lint_javascript_cli
    status: na
  - task: lint_javascript_examples
    status: na
  - task: lint_javascript_tests
    status: na
  - task: lint_javascript_benchmarks
    status: na
  - task: lint_python
    status: na
  - task: lint_r
    status: passed
  - task: lint_c_src
    status: na
  - task: lint_c_examples
    status: na
  - task: lint_c_benchmarks
    status: na
  - task: lint_c_tests_fixtures
    status: na
  - task: lint_shell
    status: na
  - task: lint_typescript_declarations
    status: na
  - task: lint_typescript_tests
    status: na
  - task: lint_license_headers
    status: passed
---

Author: Prog-Jacob

tools/lint/r/linter.R

@@ -25,8 +25,8 @@
 # [1]: https://github.com/jimhester/lintr
 
 # Ensure that the `lintr` package is installed...
-if ( !require( 'lintr', quietly = TRUE, character.only = TRUE ) ) {
-	install.packages( 'lintr', repos = 'http://lib.stat.cmu.edu/R/CRAN/', quiet = TRUE );
+if ( !requireNamespace( 'lintr', quietly = TRUE, character.only = TRUE ) ) {
+	install.packages( 'lintr', repos = 'https://archive.linux.duke.edu/cran/', quiet = TRUE );
 }
 
 # Get only the trailing command-line arguments:
@@ -39,7 +39,7 @@ if ( n == 0L ) {
 }
 
 # Specify which linters to use...
-linters <- lintr::linters_with_defaults( defaults = default_linters,
+linters <- lintr::linters_with_defaults( defaults = lintr::default_linters,
 	# Check that no absolute paths are used:
 	absolute_path_linter = lintr::absolute_path_linter(),
 
@@ -111,7 +111,7 @@ linters <- lintr::linters_with_defaults( defaults = default_linters,
 	T_and_F_symbol_linter = lintr::T_and_F_symbol_linter(),
 
 	# Report the use of undesirable functions (e.g., `attach` or `sapply`) and suggest an alternative:
-	undesirable_function_linter = lintr::undesirable_function_linter( fun = within( default_undesirable_functions, rm( options ) ) ),
+	undesirable_function_linter = lintr::undesirable_function_linter( fun = within( lintr::default_undesirable_functions, rm( options ) ) ),
 
 	# Report the use of undesirable operators (e.g., `:::` or `<<-`) and suggest an alternative:
 	undesirable_operator_linter = lintr::undesirable_operator_linter(),

tools/scripts/install_r_pkgs.R

@@ -26,10 +26,10 @@ args <- commandArgs( trailingOnly = TRUE );
 
 # Check that at least one package name has been provided...
 n <- length( args );
-if ( n == 0 ) {
-	stop( "Must provide at least one package to install.", call. = FALSE );
+if ( n == 0L ) {
+	stop( 'Must provide at least one package to install.', call. = FALSE );
 }
 # Install each package...
-for ( i in 1:n ) {
-	install.packages( args[ i ], repos = "http://lib.stat.cmu.edu/R/CRAN/" );
+for ( i in 1L:n ) {
+	install.packages( args[ i ], repos = 'https://archive.linux.duke.edu/cran/' );
 }