Add a test for :main and :run

testsuite/tests/ghc-regress/ghci/scripts/all.T

@@ -39,6 +39,7 @@ test('ghci026', normal, ghci_script, ['ghci026.script'])
 
 test('ghci027', normal, ghci_script, ['ghci027.script'])
 test('ghci028', normal, ghci_script, ['ghci028.script'])
+test('ghci029', normal, ghci_script, ['ghci029.script'])
 
 test('1914', if_compiler_ge('ghc', '6.9', expect_broken(2034)),
              ghci_script, ['1914.script'])

testsuite/tests/ghc-regress/ghci/scripts/ghci029.script

+-- :main and :run
+let main = System.Environment.getArgs >>= print
+:main foo bar
+:main foo "bar baz"
+:main ["foo", "bar baz"]
+let foo = putStrLn "foo" >> System.Environment.getArgs >>= print
+let bar = putStrLn "bar" >> System.Environment.getArgs >>= print
+:set -main-is foo
+:main foo "bar baz"
+:run bar ["foo", "bar baz"]
+

testsuite/tests/ghc-regress/ghci/scripts/ghci029.stdout

+["foo","bar"]
+["foo","bar baz"]
+["foo","bar baz"]
+foo
+["foo","bar baz"]
+bar
+["foo","bar baz"]