%{
/*
 * scan.l
 *
 * lex input file for pascal scanner
 *
 * extensions: two ways to spell "external" and "->" ok for "^".
 */

#include "gram.tab.h"
int line_no = 1;

%}

A       [aA]
B       [bB]
C       [cC]
D       [dD]
E       [eE]
F       [fF]
G       [gG]
H       [hH]
I       [iI]
J       [jJ]
K       [kK]
L       [lL]
M       [mM]
N       [nN]
O       [oO]
P       [pP]
Q       [qQ]
R       [rR]
S       [sS]
T       [tT]
U       [uU]
V       [vV]
W       [wW]
X       [xX]
Y       [yY]
Z       [zZ]
NQUOTE  [^']

%%

{A}{N}{D}                       return(AND);
{A}{R}{R}{A}{Y}                 return(ARRAY);
{C}{A}{S}{E}                    return(CASE);
{C}{O}{N}{S}{T}                 return(CONST);
{D}{I}{V}                       return(DIV);
{D}{O}                          return(DO);
{D}{O}{W}{N}{T}{O}              return(DOWNTO);
{E}{L}{S}{E}                    return(ELSE);
{E}{N}{D}                       return(END);
{E}{X}{T}{E}{R}{N}      |
{E}{X}{T}{E}{R}{N}{A}{L}        return(EXTERNAL);
{F}{O}{R}                       return(FOR);
{F}{O}{R}{W}{A}{R}{D}           return(FORWARD);
{F}{U}{N}{C}{T}{I}{O}{N}        return(FUNCTION);
{G}{O}{T}{O}                    return(GOTO);
{I}{F}                          return(IF);
{I}{N}                          return(IN);
{L}{A}{B}{E}{L}                 return(LABEL);
{M}{O}{D}                       return(MOD);
{N}{I}{L}                       return(NIL);
{N}{O}{T}                       return(NOT);
{O}{F}                          return(OF);
{O}{R}                          return(OR);
{O}{T}{H}{E}{R}{W}{I}{S}{E}     return(OTHERWISE);
{P}{A}{C}{K}{E}{D}              return(PACKED);
{B}{E}{G}{I}{N}                 return(PBEGIN);
{F}{I}{L}{E}                    return(PFILE);
{P}{R}{O}{C}{E}{D}{U}{R}{E}     return(PROCEDURE);
{P}{R}{O}{G}{R}{A}{M}           return(PROGRAM);
{R}{E}{C}{O}{R}{D}              return(RECORD);
{R}{E}{P}{E}{A}{T}              return(REPEAT);
{S}{E}{T}                       return(SET);
{T}{H}{E}{N}                    return(THEN);
{T}{O}                          return(TO);
{T}{Y}{P}{E}                    return(TYPE);
{U}{N}{T}{I}{L}                 return(UNTIL);
{V}{A}{R}                       return(VAR);
{W}{H}{I}{L}{E}                 return(WHILE);
{W}{I}{T}{H}                    return(WITH);
[a-zA-Z]([a-zA-Z0-9])*          return(IDENTIFIER);

":="                            return(ASSIGNMENT);
'({NQUOTE}|'')+'                return(CHARACTER_STRING);
":"                             return(COLON);
","                             return(COMMA);
[0-9]+                          return(DIGSEQ);
"."                             return(DOT);
".."                            return(DOTDOT);
"="                             return(EQUAL);
">="                            return(GE);
">"                             return(GT);
"["                             return(LBRAC);
"<="                            return(LE);
"("                             return(LPAREN);
"<"                             return(LT);
"-"                             return(MINUS);
"<>"                            return(NOTEQUAL);
"+"                             return(PLUS);
"]"                             return(RBRAC);
[0-9]+"."[0-9]+                 return(REALNUMBER);
")"                             return(RPAREN);
";"                             return(SEMICOLON);
"/"                             return(SLASH);
"*"                             return(STAR);
"**"                            return(STARSTAR);
"->"                    |
"^"                             return(UPARROW);

"(*"                    |
"{"                             { register int c;
                                        while ((c = input()))
                                        {
                                                if (c == '}')
                                                        break;
                                                else if (c == '*')
                                                {
                                                        if ((c = input()) == ')')
                                                                break;
                                                        else
                                                                unput (c);
                                                }
                                                else if (c == '\n')
                                                        line_no++;
                                                else if (c == 0)
                                                        commenteof();
                                        }
                                }

[ \t\f]                         ;

\n                              line_no++;

.                               { fprintf (stderr,
                                "'%c' (0%o): illegal charcter at line %d\n",
                                        yytext[0], yytext[0], line_no);
                                }

%%

commenteof()
{
        fprintf (stderr, "unexpected EOF inside comment at line %d\n",
                line_no);
        exit (1);
}