mirror of https://github.com/bsnes-emu/bsnes.git
100 lines
2.5 KiB
C++
Executable File
100 lines
2.5 KiB
C++
Executable File
#pragma once
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namespace nall::Eval {
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inline auto isLiteral(const char*& s) -> bool {
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char n = s[0];
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return (n >= 'A' && n <= 'Z')
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|| (n >= 'a' && n <= 'z')
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|| (n >= '0' && n <= '9')
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|| (n == '%' || n == '$' || n == '_' || n == '.')
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|| (n == '\'' || n == '\"');
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}
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inline auto literalNumber(const char*& s) -> string {
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const char* p = s;
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//binary
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if(p[0] == '%' || (p[0] == '0' && p[1] == 'b')) {
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uint prefix = 1 + (p[0] == '0');
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p += prefix;
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while(p[0] == '\'' || p[0] == '0' || p[0] == '1') p++;
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if(p - s <= prefix) throw "invalid binary literal";
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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//octal
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if(p[0] == '0' && p[1] == 'o') {
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uint prefix = 1 + (p[0] == '0');
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p += prefix;
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while(p[0] == '\'' || (p[0] >= '0' && p[0] <= '7')) p++;
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if(p - s <= prefix) throw "invalid octal literal";
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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//hex
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if(p[0] == '$' || (p[0] == '0' && p[1] == 'x')) {
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uint prefix = 1 + (p[0] == '0');
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p += prefix;
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while(p[0] == '\'' || (p[0] >= '0' && p[0] <= '9') || (p[0] >= 'A' && p[0] <= 'F') || (p[0] >= 'a' && p[0] <= 'f')) p++;
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if(p - s <= prefix) throw "invalid hex literal";
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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//decimal
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while(p[0] == '\'' || (p[0] >= '0' && p[0] <= '9')) p++;
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if(p[0] != '.') {
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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//floating-point
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p++;
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while(p[0] == '\'' || (p[0] >= '0' && p[0] <= '9')) p++;
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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inline auto literalString(const char*& s) -> string {
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const char* p = s;
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char escape = *p++;
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while(p[0] && p[0] != escape) p++;
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if(*p++ != escape) throw "unclosed string literal";
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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inline auto literalVariable(const char*& s) -> string {
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const char* p = s;
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while(p[0] == '_' || p[0] == '.' || (p[0] >= 'A' && p[0] <= 'Z') || (p[0] >= 'a' && p[0] <= 'z') || (p[0] >= '0' && p[0] <= '9')) p++;
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string result = slice(s, 0, p - s);
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s = p;
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return result;
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}
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inline auto literal(const char*& s) -> string {
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const char* p = s;
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if(p[0] >= '0' && p[0] <= '9') return literalNumber(s);
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if(p[0] == '%' || p[0] == '$') return literalNumber(s);
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if(p[0] == '\'' || p[0] == '\"') return literalString(s);
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if(p[0] == '_' || p[0] == '.' || (p[0] >= 'A' && p[0] <= 'Z') || (p[0] >= 'a' && p[0] <= 'z')) return literalVariable(s);
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throw "invalid literal";
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}
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}
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