JFlex Lexer. Multiline strings

Question

JFlex Lexer. Multiline strings

I am trying to parse some language with multi-line string literals using JFlex.

Examples:

'''
this is a valid multiline string literal with 'quoted' word
'''

I created two states:

%x IN_QUOTED_STRING
%x IN_MULTILINE_QUOTED_STRING

and created some macros and rules:

QUOTED_STRING_TAIL=[^\']* "'"
QUOTED_STRING_START="@"? "'"
MULTILINE_QUOTED_STRING_START = "@"? "'''"
MULTILINE_QUOTED_STRING_TAIL = [.]* "'''"

%%

<YYINITIAL> {MULTILINE_QUOTED_STRING_START} {yybegin(IN_MULTILINE_QUOTED_STRING);}
<YYINITIAL> {QUOTED_STRING_START} {yybegin(IN_QUOTED_STRING);}

<IN_QUOTED_STRING> {QUOTED_STRING_TAIL} {yybegin(YYINITIAL); return STRING;}
<IN_MULTILINE_QUOTED_STRING> {MULTILINE_QUOTED_STRING_TAIL} {yybegin(YYINITIAL); return STRING;}

But that will not work. I get the message "Error: input failed"

Can someone help me with proplem?

+5

string multiline jflex lexer

fkorotkov May 12 '12 at 10:07

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1 answer

Brian Tompsett - 汤莱恩 · Answer 1 · 2015-05-14T18:50:16+0000

OP wrote (a):

works for me:

QUOTED_LITERAL="'" ([^\\\'\r\n] | {ESCAPE_SEQUENCE} | (\[\r\n]))* ("'"|\)?
ESCAPE_SEQUENCE=\[^\r\n] 
ANY_ESCAPE_SEQUENCE = \[^] 
THREE_QUO = (\"\"\") 
ONE_TWO_QUO = (\"[^\"]) | (\"\[^]) | (\"\"[^\"]) | (\"\"\[^]) 
QUO_STRING_CHAR = [^\\\"] | {ANY_ESCAPE_SEQUENCE} | {ONE_TWO_QUO}
TRIPLE_QUOTED_LITERAL = {THREE_QUO} {QUO_STRING_CHAR}* {THREE_QUO}?
%%
<YYINITIAL> {TRIPLE_QUOTED_LITERAL }{ return STRING; } 
<YYINITIAL> {QUOTED_LITERAL} { return STRING; }

JFlex Lexer. Multiline strings

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