grammar.hh

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#include "Pegmatite/pegmatite.hh"
namespace Parser
{
    using pegmatite::Rule;
    using pegmatite::operator""_E;
    using pegmatite::operator""_S;
    using pegmatite::ExprPtr;
    using pegmatite::BindAST;
    using pegmatite::any;
    using pegmatite::nl;
    using pegmatite::trace;

struct MysoreScriptGrammar
{
    Rule whitespace  = ' '_E | '\t' | nl('\n');
    Rule comment     = ("/*"_E >>
                       (*(!ExprPtr("*/") >> (nl('\n') | any()))) >>
                       "*/") |
                       "//"_E >> *(!(ExprPtr("\n")) >> any()) >> nl('\n');
    Rule ignored     = *(comment | whitespace);
    ExprPtr digit = '0'_E - '9';
    Rule num    = -("+-"_S) >> +digit;
    Rule val    = num |  '(' >> arith_expr >> ')';
    Rule mul_op = mul >> '*' >> val;
    Rule div_op = mul >> '/' >> val;
    Rule mul    = mul_op | div_op | val;
    Rule add_op = arith_expr >> '+' >> arith_expr;
    Rule sub_op = arith_expr >> '-' >> arith_expr;
    Rule ne_cmp = arith_expr >> "!=" >> arith_expr;
    Rule eq_cmp = arith_expr >> "==" >> arith_expr;
    Rule lt_cmp = arith_expr >> '<' >> arith_expr;
    Rule gt_cmp = arith_expr >> '>' >> arith_expr;
    Rule le_cmp = arith_expr >> "<=" >> arith_expr;
    Rule ge_cmp = arith_expr >> ">=" >> arith_expr;
    Rule cmp    = eq_cmp | ne_cmp | lt_cmp | gt_cmp | le_cmp | ge_cmp;
    Rule arith_expr   = add_op | sub_op | mul | cmp | expression;
    ExprPtr character = term(("\\\""_E | !ExprPtr('"') >> (nl('\n') | any())));
    Rule string_body      = *character;
    Rule string  = term('"' >> string_body >> '"');
    ExprPtr letter    = (('a'_E - 'z') | ('A'_E - 'Z'));
    Rule identifier   = term(letter >> *(letter | digit));
    Rule argList      = '('_E >> -(identifier >> *(',' >> identifier)) >> ')';
    Rule closure      = "func"_E  >> identifier >> argList >>
                        '{' >> statements >> '}';
    Rule variable     = identifier;
    Rule assignment   = variable >> '=' >> expression;
    Rule callArgList  = '('_E >> -(expression >> *(',' >> expression)) >> ')';
    Rule call         = callable >> -('.'_E >> identifier) >> callArgList;
    Rule callable     = closure | newExpr | arith_expr | variable | string |
                        call;
    Rule expression   = call | closure | newExpr | arith_expr | variable |
                        string;
    Rule newExpr      = "new"_E >> identifier;
    Rule decl         = "var"_E >> identifier >> -('='_E >> expression) >> ';';
    Rule ret          = "return"_E >> expression >> ';';
    Rule ifStatement  = "if"_E >> '(' >> expression >> ')' >>
                        '{' >> statements >> '}';
    Rule whileLoop    = "while"_E >> '(' >> expression >> ')' >>
                        '{' >> statements >> '}';
    Rule cls          = "class"_E >> identifier >> -(':'_E >> identifier) >> '{'
                         >> *decl >> *closure >> '}';
    Rule statement    = cls | ret | ifStatement | whileLoop | decl |
                        ((assignment | expression) >> ';');
    Rule statements   = *(statement);
    static const MysoreScriptGrammar& get()
    {
        static MysoreScriptGrammar g;
        return g;
    }
    private:
    MysoreScriptGrammar() {};
};
}