81 lines
2.2 KiB
Plaintext
81 lines
2.2 KiB
Plaintext
<<
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fn mylexfn(context: &mut p_context_t, out_token_info: &mut p_token_info_t) -> usize {
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loop {
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if context.expanding {
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let ei = context.expand_i;
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context.expand_i += 1;
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if context.expand_i >= context.token_infos.len() {
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context.expanding = false;
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}
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*out_token_info = context.token_infos[ei].clone();
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return P_SUCCESS;
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}
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let lex_result = p_lex(context, out_token_info);
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if lex_result != P_SUCCESS {
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return lex_result;
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}
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if out_token_info.token == TOKEN_macro {
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context.defining = true;
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} else if out_token_info.token == TOKEN_macroname {
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if !context.defining {
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context.expanding = true;
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context.expand_i = 0;
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continue;
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}
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} else if out_token_info.token == TOKEN_lbrace {
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if context.defining {
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/* Capture the macro body tokens (up to the closing '}'). */
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let mut infos: Vec<p_token_info_t> = Vec::new();
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loop {
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let mut ti = p_token_info_t::default();
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assert_eq!(P_SUCCESS, p_lex(context, &mut ti));
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if ti.token == TOKEN_rbrace {
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break;
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}
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infos.push(ti);
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}
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context.token_infos = infos;
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context.defining = false;
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}
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} else {
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context.defining = false;
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}
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return lex_result;
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}
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}
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>>
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context_user_fields <<
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pub defining: bool,
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pub expanding: bool,
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pub expand_i: usize,
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pub token_infos: Vec<p_token_info_t>,
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pub nums: Vec<i64>,
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>>
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ptype i64;
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lex_fn mylexfn;
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drop /\s+/;
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token lbrace /\{/;
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token rbrace /\}/;
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token plus /\+/;
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token macro;
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token macroname /@[a-zA-Z_]\w*/;
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token num /\d+/ <<
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let mut v: i64 = 0;
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for c in match_ { v = v * 10 + (*c - b'0') as i64; }
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$$ = v;
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>>
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Start -> Statements;
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Statements -> ;
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Statements -> Statement Statements;
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Statement -> Add;
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Statement -> MacroStart;
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Add -> num plus num << $$ = $1 + $3; ${context.nums}.push($$); >>
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MacroStart -> macro macroname lbrace;
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