The Extended Syntax Rules

5.2 The Extended Syntax Rules

<function> ::= ftype PROCEDURE id (<id list>); <statement>; = ⇒

= ⇒

(PUTD

(QUOTE id)

(QUOTE ftype)

(QUOTE (LAMBDA (<id list>) <statement>)))

<id list> ::= id

id ∣

id, <id list>

id <id list> ∣

NIL

<statement> ::= <expression>

<expression> ∣

<proper statement> = ⇒

= ⇒

<proper statement>

<proper statement> ::=

<assignment statement>

<assignment statement> ∣

<conditional statement>

<conditional statement> ∣

<while statement>

<while statement> ∣

<compound statement>

<compound statement>

<assignment statement> ::= id := <expression> = ⇒

= ⇒

(SETQ id <expression>)

<conditional statement> ::=

IF <expression> THEN <statement₁> ELSE <statement₂>

(COND (<expression> <statement₁>)(T <statement₂>)) ∣

IF <expression> THEN <statement> = ⇒

= ⇒

(COND (<expression> <statement>))

<while statement> ::= WHILE <expression> DO <statement> = ⇒

= ⇒

(PROG NIL

LBL

(COND ((NULL <expression>) (RETURN NIL)))

<statement>

(GO LBL))

<compound statement> ::=

BEGIN SCALAR <id list>; <program list> END = ⇒

= ⇒

(PROG (<id list>) <program list>) ∣

BEGIN <program list> END = ⇒

= ⇒

(PROG NIL <program list>) ∣

<< <statement list> >>

(PROGN <statement list>)

<program list> ::= <full statement>

<full statement> ∣

<full statement> <program list> = ⇒

= ⇒

<full statement> <program list>

<full statement> ::= <statement> = ⇒

= ⇒

<statement> ∣ id:

id

<statement list> ::= <statement> = ⇒

= ⇒

<statement> ∣

<statement>; <statement list> = ⇒

= ⇒

<statement> <statement list>

<expression> ::=

<expression₁> . <expression₂> = ⇒

= ⇒

(CONS <expression₁> <expression₂> ∣

<expression₁> = <expression₂> = ⇒

= ⇒

(EQUAL <expression₁> <expression₂>) ∣

<expression₁> EQ <expression₂> = ⇒

= ⇒

(EQ <expression₁> <expression₂>) ∣

’<expression>

(QUOTE <expression>) ∣

function <expression>

(function <expression>) ∣

function(<argument list>)

(function <argument list>) ∣

number

number ∣

id

id

<argument list> ::= ()

∣

<expression>

<expression> ∣

<expression>, <argument list>

<expression> <argument list>

Notice the three infix operators . EQ and = which are translated into calls on CONS, EQ, and EQUAL respectively. Note also that a call on a function which has no formal parameters must have () as an argument list. The QUOTE function is abbreviated by ’.