A personal scheme interpreter

• Double precision numbers ::= AE
• Strings ::= STR
• Boolean ::= BE
• Symbols ::= SE

• define ::= (define SE E) -> None -- Binds the result of the expression E to the symbolic expression SE. Ex:
  • (define a 5)
• if ::= (if BE E E) -> E -- evaluates to the first E (the consequent) if the condition is true, otherwise evaluates to the second E (the alternate). Ex:
  • (if true 5 4)
• import ::= (import STR) -> None -- imports and interprets the given filename into the current environment line by line.
  • (import "arithmetic")

• + ::= (+ AE AE) -> AE
• - ::= (- AE AE) -> AE
• * ::= (* AE AE) -> AE
• / ::= (/ AE AE) -> AE

• and ::= (and BE BE) -> BE
• or ::= (or BE BE) -> BE
• not ::= (not BE) -> BE

• < ::= (< AE AE) -> BE
• <= ::= (<= AE AE) -> BE
• == ::= (== AE AE) -> BE
• >= ::= (>= AE AE) -> BE
• > ::= (> AE AE) -> BE

expr ::= sexpr | literal
sexpr ::= "(" SYMBOL expr* ")"
literal ::= NUMBER | SYMBOL | BOOLEAN | STRING | CHARACTER
SYMBOL ::= /[A-Za-z_][0-9A-Za-z_]*/
NUMBER ::= /[-+]?([0-9]*\.?[0-9]+|[0-9]+)/
BOOLEAN ::= /true/ | /false/
STRING ::= <traditional c-string syntax, including escapes>
CHARACTER ::= /'\c'/

• Number
• Boolean
• String
• Character
• Pair
• Closure

• bind ::=
  • (bind SYMBOL expr) -> binds the value of the given sexpr to the given SYMBOL in the env
  • (bind sexpr expr) -> creates a function whose named binding is the first SYMBOL of the sexpr given.
• lambda
• print ::=
  • (print expr) -> prints the value of the given expression
• import
• true
• false
• and
• or
• not
• if
• cons
• car
• cdr
• null