_M_i_r_a_n_d_a_ _l_e_x_i_c_a_l_ _s_y_n_t_a_x
 In this section square brackets are used to enclose a  set  of  literal
characters,  using lex-style conventions, so eg [a-z] means a lower case
letter.   As  usual  *  and  ?   are  used  to  mean  zero-or-more,  and
zero-or-one,  occurrences of the preceding entity.  Parentheses are used
for grouping, and subtraction of one syntactic entity from another means
set  difference.   We  also  revert to using `|' for alternatives, as in
standard BNF.

script:= (token | layout)*

layout:= nl | tab | formfeed | space | comment

comment:= vertical_bar vertical_bar (any - nl)* nl

token:= identifier | IDENTIFIER | literal | typevar | delimiter

identifier:= ([a-z] [a-zA-Z0-9_']* ) -  delimiter

IDENTIFIER:= [A-Z] [a-zA-Z0-9_']*

literal:= numeral | charconst | stringconst

literal1:= literal - float

numeral:= nat | float

nat:= [0-9] [0-9]* | 0x [0-9a-f] [0-9a-f]* | 0o [0-7] [0-7]*

float:=  [0-9]* [.] nat epart? | nat epart

epart:= [e] [+|-]? nat

charconst:= ['] (visible-[\]|escape) [']

stringconst:= ["] (visible-[\"]|escape)* ["]

escape:= [\] ([ntfrb\'"]|nl|decimal_code)

typevar:= [*][*]*

delimiter:= - | prefix1 | infix1 | other

infix1:= ++ | -- | : | \/ | & | > | >= | = | ~= | <= | < | + | * |
         / | div | mod | ^ | . | ! | $identifier | $IDENTIFIER

infix:= infix1 | -

prefix1:= ~ | #

prefix:= prefix1 | -

other:= abstype | if | otherwise | readvals | show | type | where |
	with | %export | %free | %include | %insert | %list | %nolist |
	= | == | ::= | :: | => | vertical_bar | // | -> | ; | , | ( |
	) | [ | ] | { | } | <- | .. | $$ | $- | $:- | $+ | $*

vertical_bar:= |

_N_o_t_e_s
 visible means any  non-control  character,  including  space  (but  not
including  eg  newline), nl means literal newline, and decimal_code is a
nat in the range 0..255 (maximum length 3 digits).

Notice that the syntax of `numeral' does not include  negative  numbers.
Negative  constants,  such  as  -3 or -5.05e-17 are parsed by Miranda as
applications of the prefix operator `-' to a positive numeral.  This has
no semantic significance.

Omission - the definition of `layout' does not  include  the  additional
comment rules for LITERATE SCRIPTS (see separate manual section).