pascalscript_lexer.g4

/*
    This file is part of the PascalScript Pascal interpreter.
    SPDX-FileCopyrightText: 2024 Christophe "CHiPs" Petit <chips44@gmail.com>
    SPDX-License-Identifier: GPL-3.0-or-later
*/

/* ******************** PascalScript ANTLR4 ******************** */

// npm i -g --save-dev antlr-format-cli
//  antlr-format -v pascalscript_lexer.g4

// $antlr-format alignTrailingComments true
// $antlr-format columnLimit 80
// $antlr-format minEmptyLines 0
// $antlr-format maxEmptyLinesToKeep 1
// $antlr-format reflowComments false
// $antlr-format useTab false
// $antlr-format allowShortRulesOnASingleLine true
// $antlr-format allowShortBlocksOnASingleLine true
// $antlr-format alignSemicolons ownLine
// $antlr-format alignColons hanging

lexer grammar pascalscript_lexer;

options {
    // needs antlr4 >= 4.10
    caseInsensitive = true;
}

/* ******************** WHITESPACE ******************** */

WHITESPACE: [ \n\t\r]+ -> skip;

/* ******************** LEXEMES ******************** */

// NB: lexer rules begin with / are uppercase

// Keywords
PROGRAM: 'PROGRAM';
/*
UNIT:           'UNIT';
USES:           'USES';
INTERFACE:      'INTERFACE';
IMPLEMENTATION: 'IMPLEMENTATION';
INITIALIZATION: 'INITIALIZATION';
FINALIZATION:   'FINALIZATION';
*/
BEGIN: 'BEGIN';
END: 'END';
IF: 'IF';
THEN: 'THEN';
ELSE: 'ELSE';
REPEAT: 'REPEAT';
UNTIL: 'UNTIL';
WHILE: 'WHILE';
DO: 'DO';
FOR: 'FOR';
TO: 'TO';
DOWNTO: 'DOWNTO';
WRITE: 'WRITE';
WRITELN: 'WRITELN';
FALSE: 'FALSE';
TRUE: 'TRUE';
LABEL: 'LABEL';
GOTO: 'GOTO';
INTEGER: 'INTEGER';
CARDINAL: 'CARDINAL';
BOOLEAN: 'BOOLEAN';
CHAR: 'CHAR';
STRING: 'STRING';
REAL: 'REAL';
ARRAY: 'ARRAY';
OF: 'OF';
RECORD: 'RECORD';
CONST: 'CONST';
TYPE: 'TYPE';
VAR: 'VAR';
PROCEDURE: 'PROCEDURE';
FUNCTION: 'FUNCTION';

// Operators
NOT: 'NOT';
OR: 'OR';
XOR: 'XOR';
DIV: 'DIV'; // division (integer)
MOD: 'MOD';
AND: 'AND';
SHL: 'SHL';
SHR: 'SHR';

// Arithmetic operators
PLUS: '+';  // addition
MINUS: '-'; // substraction / negation
STAR: '*';  // multiplication
SLASH: '/'; // division (real)

// Comparison operators
EQUAL: '=';
NOT_EQUAL: '<>';
LESS_THAN: '<';
LESS_OR_EQUAL: '<=';
GREATER_THAN: '>';
GREATER_OR_EQUAL: '>=';

// Symbols
DOT_COLON: ':=';        // assignment
AT_SIGN: '@';           // address of
CARET: '^';             // pointer to
COLON: ':';             // various uses
COMMA: ',';             // various uses
DOT_DOT: '..';          // ranges
DOT: '.';               // various uses
LEFT_BRACKET: '[';      // array access
LEFT_PARENTHESIS: '(';  // various uses
RIGHT_BRACKET: ']';     // array access
RIGHT_PARENTHESIS: ')'; // various uses
SEMI_COLON: ';';        // various uses
UNDERSCORE: '_';        // identifier part
QUOTE: '\'';            // char/string delimiter
PERCENT: '%';           // binary prefix
AMPERSAND: '&';         // octal prefix
DOLLAR: '$';            // hexadecimal prefix

/* ******************** IDENTIFIER ******************** */

IDENTIFIER
    : IDENTIFIER_PREFIX
    | IDENTIFIER_PREFIX (
        LETTER
        | DECIMAL_DIGIT
        | UNDERSCORE
    )+
;

IDENTIFIER_PREFIX: LETTER | UNDERSCORE;

LETTER: 'A' ..'Z';

/* ******************** NUMBERS ******************** */

UNSIGNED_INTEGER_VALUE
    : DECIMAL_DIGIT_SEQUENCE
    | PERCENT BINARY_DIGIT_SEQUENCE
    | AMPERSAND OCTAL_DIGIT_SEQUENCE
    | DOLLAR HEXADECIMAL_DIGIT_SEQUENCE
;

UNSIGNED_REAL_VALUE
    : DECIMAL_DIGIT_SEQUENCE DOT DECIMAL_DIGIT_SEQUENCE (
        'E'? SIGN? DECIMAL_DIGIT_SEQUENCE
    )?
;

DECIMAL_DIGIT_SEQUENCE: DECIMAL_DIGIT+;

BINARY_DIGIT_SEQUENCE: BINARY_DIGIT+;

OCTAL_DIGIT_SEQUENCE: OCTAL_DIGIT+;

HEXADECIMAL_DIGIT_SEQUENCE: HEXADECIMAL_DIGIT+;

SIGN: PLUS | MINUS;

DECIMAL_DIGIT: '0' ..'9';

BINARY_DIGIT: '0' ..'1';

OCTAL_DIGIT: '0' ..'7';

HEXADECIMAL_DIGIT: '0' ..'9' | 'A' ..'F';

/* ******************** CHARS & STRINGS ******************** */

CHARACTER_VALUE: QUOTED_CHAR | CONTROL_CHAR;

COMPOSED_STRING_VALUE
    : (QUOTED_STRING | CONTROL_CHAR)+
;

// Any printable character from C0 (ASCII) & C1 Unicode blocks except ' (#39 / \u0027)
CHAR_VALUE
    // C0 / ASCII
    : '\u0020' ..'\u0026'
    | '\u0028' ..'\u007e'
    // C1 / LATIN1
    | '\u00a0' ..'\u00ff'
    | '\'\''
;

// #13 as CR, #10 as LF, #$1B as ESC, ...
CONTROL_CHAR: '#' UNSIGNED_INTEGER_VALUE;

// Single character
QUOTED_CHAR: QUOTE CHAR_VALUE QUOTE;

QUOTED_STRING: QUOTE (CHAR_VALUE)* QUOTE;

/* ******************** BOOLEANS ******************** */

BOOLEAN_VALUE: FALSE | TRUE;

/* ******************** COMMENTS ******************** */

ANY_CHAR: .;

COMMENT1: '(*' ANY_CHAR* '*)' -> skip;

COMMENT2: '{' ANY_CHAR* '}' -> skip;

COMMENT3: '//' ANY_CHAR* '\n' -> skip;

// EOF