Add startup argument and flowr config file entry for changing the R s…

…hell's R executable (#718)

src/config.ts

@@ -11,10 +11,15 @@ export interface FlowrConfigOptions extends MergeableRecord {
 	 * Whether source calls should be ignored, causing {@link processSourceCall}'s behavior to be skipped
 	 */
 	ignoreSourceCalls: boolean
+	/**
+	 * The path to the R executable to use. If this is undefined, {@link DEFAULT_R_PATH} will be used.
+	 */
+	rPath:             string | undefined
 }
 
 export const defaultConfigOptions: FlowrConfigOptions = {
-	ignoreSourceCalls: false
+	ignoreSourceCalls: false,
+	rPath:             undefined
 }
 export const defaultConfigFile = 'flowr.json'
 

src/flowr.ts

@@ -37,7 +37,8 @@ export const optionDefinitions: OptionDefinition[] = [
 	{ name: 'execute',      alias: 'e', type: String,  description: 'Execute the given command and exit. Use a semicolon ";" to separate multiple commands.', typeLabel: '{underline command}', multiple: false },
 	{ name: 'no-ansi',                  type: Boolean, description: 'Disable ansi-escape-sequences in the output. Useful, if you want to redirect the output to a file.' },
 	{ name: 'script',       alias: 's', type: String,  description: `The sub-script to run (${scriptsText})`, multiple: false, defaultOption: true, typeLabel: '{underline files}', defaultValue: undefined },
-	{ name: 'config-file', type: String, description: 'The name of the configuration file to use', multiple: false }
+	{ name: 'config-file', type: String, description: 'The name of the configuration file to use', multiple: false },
+	{ name: 'r-path', type: String, description: 'The path to the R executable to use. Defaults to your PATH.', multiple: false }
 ]
 
 export interface FlowrCliOptions {
@@ -51,6 +52,7 @@ export interface FlowrCliOptions {
 	execute:       string | undefined
 	script:        string | undefined
 	'config-file': string
+	'r-path':      string | undefined
 }
 
 export const optionHelp = [
@@ -95,6 +97,7 @@ function retrieveShell(): RShell {
 			console.log(formatter.format(`R process exited with code ${code}${signalText}. Restarting...`, { color: Colors.Magenta, effect: ColorEffect.Foreground }))
 			console.log(italic(`If you want to exit, press either Ctrl+C twice, or enter ${bold(':quit')}`))
 		},
+		pathToRExecutable: options['r-path']
 	})
 }
 

src/r-bridge/shell.ts

@@ -8,6 +8,7 @@ import type { SemVer } from 'semver'
 import semver from 'semver/preload'
 import { getPlatform } from '../util/os'
 import fs from 'fs'
+import { getConfig } from '../config'
 
 export type OutputStreamSelector = 'stdout' | 'stderr' | 'both';
 
@@ -89,8 +90,9 @@ export interface RShellOptions extends RShellSessionOptions {
 	readonly sessionName: string
 }
 
+export const DEFAULT_R_PATH = getPlatform() === 'windows' ? 'R.exe' : 'R'
 export const DEFAULT_R_SHELL_EXEC_OPTIONS: RShellExecutionOptions = {
-	pathToRExecutable:  getPlatform() === 'windows' ? 'R.exe' : 'R',
+	pathToRExecutable:  getConfig().rPath ?? DEFAULT_R_PATH,
 	commandLineOptions: ['--vanilla', '--quiet', '--no-echo', '--no-save'],
 	cwd:                process.cwd(),
 	env:                process.env,