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restart-mzscheme

 (require mzlib/restart)

See scheme/sandbox for a more general way to simulate running a new Racket process.

(restart-mzscheme init-argv    
  adjust-flag-table    
  argv    
  init-namespace)  boolean?
  init-argv : (vectorof string?)
  adjust-flag-table : (any/c . -> . any/c)
  argv : (vectorof string?)
  init-namespace : (-> any)
Simulates starting Racket with the vector of command-line strings argv. The init-argv, adjust-flag-table, and init-namespace arguments are used to modify the default settings for command-line flags, adjust the parsing of command-line flags, and customize the initial namespace, respectively.

The vector of strings init-argv is read first with the standard Racket command-line parsing. Flags that load files or evaluate expressions (e.g., -f and -e) are ignored, but flags that set Racket’s modes (e.g., -c or -j) effectively set the default mode before argv is parsed.

Before argv is parsed, the procedure adjust-flag-table is called with a command-line flag table as accepted by parse-command-line. The return value must also be a table of command-line flags, and this table is used to parse argv. The intent is to allow adjust-flag-table to add or remove flags from the standard set.

After argv is parsed, a new thread and a namespace are created for the “restarted” Racket. (The new namespace is installed as the current namespace in the new thread.) In the new thread, restarting performs the following actions:

Before evaluating command-line arguments, an exit handler is installed that immediately returns from restart-mzscheme with the value supplied to the handler. This exit handler remains in effect when read-eval-print-loop is called (unless a command-line argument changes it). If restart-mzscheme returns normally, the return value is determined as described above.

Note that an error in a command-line expression followed by read-eval-print-loop produces a #t result. This is consistent with Racket’s stand-alone behavior.