Experimental scanner: keeping track of octal numbers octal escapes.

src/lexer/lexer_py.re

Index: src/lexer/lexer_py.re
diff --git a/src/lexer/lexer_py.re b/src/lexer/lexer_py.re
index f347fe6df4d117771177328c07252ba35e5574f4..df03fe7c758da990205bcd7ca61e11882da946a8 100644
--- a/src/lexer/lexer_py.re
+++ b/src/lexer/lexer_py.re
@@ -32,6 +32,7 @@ digit = [0-9];
 hex_digit = [0-9a-fA-F];
 single_escape_char = ['"\\bfnrtv];
 maybe_exponent = /([eE][\-+]?[:digit:]+)?/;
+octal_number = /0[0-7]+/;
 number =
   /0[xX][:hex_digit:]+/ | (
   /\.[:digit:]+/ maybe_exponent |
@@ -96,6 +97,7 @@ eos = [:eos:];
 "<"           <|token(LT)|>
 ">"           <|token(GT)|>
 
+octal_number            <|octal_number|>
 number                  <|token(NUMBER)|>
 number identifier_char  <|token(ILLEGAL)|>
 number "\\"             <|token(ILLEGAL)|>
@@ -199,7 +201,9 @@ default_action  <do_token_and_go_forward(ILLEGAL)>
 "\\" line_terminator_sequence <||continue>
 /\\[x][:hex_digit:]{2}/       <set_has_escapes||continue>
 /\\[u][:hex_digit:]{4}/       <set_has_escapes||continue>
-/\\[^xu:line_terminator:]/    <set_has_escapes||continue>
+/\\[1-7]/                     <octal_inside_string||continue>
+/\\[0-7]{2,3}/                <octal_inside_string||continue>
+/\\[^xu1-7:line_terminator:]/ <set_has_escapes||continue>
 "\\"                          <|token(ILLEGAL)|>
 line_terminator               <|token(ILLEGAL)|>
 "\""                          <|token(STRING)|>
@@ -211,7 +215,9 @@ catch_all                     <||continue>
 "\\" line_terminator_sequence <||continue>
 /\\[x][:hex_digit:]{2}/       <set_has_escapes||continue>
 /\\[u][:hex_digit:]{4}/       <set_has_escapes||continue>
-/\\[^xu:line_terminator:]/    <set_has_escapes||continue>
+/\\[1-7]/                     <octal_inside_string||continue>
+/\\[0-7]{2,3}/                <octal_inside_string||continue>
+/\\[^xu1-7:line_terminator:]/ <set_has_escapes||continue>
 "\\"                          <|token(ILLEGAL)|>
 line_terminator               <|token(ILLEGAL)|>
 "'"                           <|token(STRING)|>