%option c++
%option noyywrap
%option yyclass="Scanner"
%x STRING

%{
#include "scanner.hpp"
#include "indent_helper.hpp"

IndentHelper indent_helper;
bool at_line_start = true;
%}

%%

^[ \t]* {
    if (!at_line_start) {
        REJECT;
    }
    at_line_start = false;

    int spaces = 0;
    for (int i = 0; i < yyleng; i++)
        spaces += (yytext[i] == '\t') ? 8 : 1;

    int result = indent_helper.processLine(spaces);
    if (result > 0) return yy::parser::token::TOK_INDENT;
    if (result < 0) return yy::parser::token::TOK_DEDENT;
}

\n {
    at_line_start = true;
    return yy::parser::token::TOK_NEWLINE;
}

def      { return yy::parser::token::TOK_KW_DEF; }
if       { return yy::parser::token::TOK_KW_IF; }
return   { return yy::parser::token::TOK_KW_RETURN; }
for      { return yy::parser::token::TOK_KW_FOR; }
in       { return yy::parser::token::TOK_KW_IN; }

\(       { return yy::parser::token::TOK_L_PAREN; }
\)       { return yy::parser::token::TOK_R_PAREN; }
\:       { return yy::parser::token::TOK_COLON; }
\=       { return yy::parser::token::TOK_ASSIGN; }
\+       { return yy::parser::token::TOK_PLUS; }
\-       { return yy::parser::token::TOK_MINUS; }

\"       { yymore(); BEGIN(STRING); }
<STRING>\"\" { yymore(); }
<STRING>\"  { BEGIN(INITIAL); yylval->as<std::string>() = yytext; return yy::parser::token::TOK_STRING; }
<STRING>.   { yymore(); }

[0-9]+      { yylval->as<std::string>() = yytext; return yy::parser::token::TOK_NUMBER; }
[A-Za-z_][A-Za-z0-9_]*  { yylval->as<std::string>() = yytext; return yy::parser::token::TOK_IDENTIFIER; }


<<EOF>> {
    if (indent_helper.hasPendingDedents()) {
        indent_helper.consumeDedent();
        return yy::parser::token::TOK_DEDENT;
    }
    int d;
    if ((d = indent_helper.flushDedent()) != 0) return yy::parser::token::TOK_DEDENT;
    return yy::parser::token::TOK_EOF;
}

.           { /* ignore other characters */ }