60 lines
1.3 KiB
Plaintext
60 lines
1.3 KiB
Plaintext
Program = lines: (Line / (_/[\n]))* {
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return { instructions: lines.filter((line) => typeof line !== "string" || line.trim() != "") };
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}
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Line = _? instruction: (LabeledInstruction / Instruction) _? [\n]? {
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return instruction;
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}
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LabeledInstruction = label:Label _ instruction:Instruction {
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return { label, instruction };
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}
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Label = "[" _? label:LABEL_V _? "]" {
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return label;
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}
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Instruction = conditional: Conditional { return { conditional }; }
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/ assignment: Assignment { return { assignment }; }
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/ goto: Goto { return { goto }; }
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Goto = GOTO _ label: LABEL_V {
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return { label };
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}
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Conditional = "IF" _ variable: VAR _? "!=" _? "0" _ goto: Goto {
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return { variable, goto };
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}
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Assignment = variable: VAR _ "<-" _ expr: Expression {
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if (expr.left != variable) {
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error("left hand variable must match right hand");
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}
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return { variable, expr };
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}
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Expression = left: VAR _ opr: OPERATION _ "1" {
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return { left, opr };
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} / left: VAR {
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return { left };
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}
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VAR = symbol:"Y" { return symbol } / symbol:("X" / "Z") ind:Integer+ {
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return symbol + ind;
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}
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GOTO = "GOTO"
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OPERATION = "+" / "-"
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LABEL_V = symbol:END_LABEL { return symbol } / symbol:[A-E] ind:Integer+ {
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return symbol + ind;
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}
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END_LABEL = "E"
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Integer "integer"
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= [0-9]+ { return parseInt(text(), 10); }
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_ "whitespace" = [ \t]+ { }
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