feat: create basic Redis grammar

src/autocomplete/databases/redis/grammar/RedisLexer.g4

@@ -0,0 +1,48 @@
+// $antlr-format alignTrailingComments true, columnLimit 500, maxEmptyLinesToKeep 1, reflowComments false, useTab false
+// $antlr-format allowShortRulesOnASingleLine true, allowShortBlocksOnASingleLine true, minEmptyLines 0, alignSemicolons ownLine
+// $antlr-format alignColons trailing, singleLineOverrulesHangingColon true, alignLexerCommands true, alignLabels true, alignTrailers true
+
+lexer grammar RedisLexer;
+
+options {
+    caseInsensitive = true;
+}
+
+// Spaces
+
+SPACE   : [ \t]+              -> channel (HIDDEN);
+NEWLINE : ('\r' '\n'? | '\n') -> channel (HIDDEN);
+
+// Keywords
+
+SET     : 'SET';
+GET     : 'GET';
+INCR    : 'INCR';
+DECR    : 'DECR';
+NX      : 'NX';
+XX      : 'XX';
+EX      : 'EX';
+PX      : 'PX';
+EXAT    : 'EXAT';
+PXAT    : 'PXAT';
+KEEPTTL : 'KEEPTTL';
+
+// Constructors symbols
+
+SINGLE_QUOTE : '\'';
+DOUBLE_QUOTE : '"';
+
+// Literal Primitives
+
+fragment DECIMAL_DIGIT: [0-9];
+
+DECIMAL_LITERAL: DECIMAL_DIGIT+;
+
+// Identifiers
+// Should be at the very bottom, for it is the most general token
+
+fragment DOUBLE_QUOTE_STRING : '"' ( '\\' . | ~('"' | '\\' | '\n' | '\r'))* '"';
+fragment SINGLE_QUOTE_STRING : '\'' ('\\' . | ~('\'' | '\\' | '\n' | '\r'))* '\'';
+fragment BASE_IDENTIFIER     : ~(' ' | '\t' | '\'' | '"' | '\n' | '\r')+;
+
+IDENTIFIER: BASE_IDENTIFIER | DOUBLE_QUOTE_STRING | SINGLE_QUOTE_STRING;

src/autocomplete/databases/redis/grammar/RedisParser.g4

@@ -0,0 +1,59 @@
+// $antlr-format columnLimit 500, minEmptyLines 1, maxEmptyLinesToKeep 1, useTab false, reflowComments false, breakBeforeBraces false
+// $antlr-format keepEmptyLinesAtTheStartOfBlocks false, allowShortRulesOnASingleLine false, alignSemicolons hanging, alignColons hanging
+// $antlr-format alignTrailingComments true
+
+parser grammar RedisParser;
+
+options {
+    tokenVocab = RedisLexer;
+}
+
+root
+    : commands? EOF
+    ;
+
+// We can omit newline only if it's the last statement
+commands
+    : command NEWLINE?
+    | command NEWLINE commands
+    ;
+
+command
+    : setCommand
+    | getCommand
+    | incrementCommand
+    | decrementCommand
+    ;
+
+setCommand
+    : SET keyName identifier (NX | XX)? GET? expirationClause?
+    ;
+
+expirationClause
+    : EX DECIMAL_LITERAL
+    | PX DECIMAL_LITERAL
+    | EXAT DECIMAL_LITERAL
+    | PXAT DECIMAL_LITERAL
+    | KEEPTTL
+    ;
+
+getCommand
+    : GET keyName
+    ;
+
+incrementCommand
+    : INCR keyName
+    ;
+
+decrementCommand
+    : DECR keyName
+    ;
+
+identifier
+    : IDENTIFIER
+    | DECIMAL_LITERAL
+    ;
+
+keyName
+    : identifier
+    ;