Dawid Sobczak
858fe11666
Moved examples to tofix because fixing them is besides the point right now.
151 lines
4.2 KiB
Lua
151 lines
4.2 KiB
Lua
local re = require 'relabel'
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local terror = {}
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local function newError(l, msg)
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table.insert(terror, { l = l, msg = msg} )
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end
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newError("errSemi", "Error: missing ';'")
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newError("errExpIf", "Error: expected expression after 'if'")
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newError("errThen", "Error: expected 'then' keyword")
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newError("errCmdSeq1", "Error: expected at least a command after 'then'")
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newError("errCmdSeq2", "Error: expected at least a command after 'else'")
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newError("errEnd", "Error: expected 'end' keyword")
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newError("errCmdSeqRep", "Error: expected at least a command after 'repeat'")
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newError("errUntil", "Error: expected 'until' keyword")
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newError("errExpRep", "Error: expected expression after 'until'")
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newError("errAssignOp", "Error: expected ':=' in assigment")
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newError("errExpAssign", "Error: expected expression after ':='")
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newError("errReadName", "Error: expected an identifier after 'read'")
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newError("errWriteExp", "Error: expected expression after 'write'")
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newError("errSimpExp", "Error: expected '(', ID, or number after '<' or '='")
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newError("errTerm", "Error: expected '(', ID, or number after '+' or '-'")
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newError("errFactor", "Error: expected '(', ID, or number after '*' or '/'")
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newError("errExpFac", "Error: expected expression after '('")
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newError("errClosePar", "Error: expected ')' after expression")
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local labelCode = {}
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for k, v in ipairs(terror) do
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labelCode[v.l] = k
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end
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re.setlabels(labelCode)
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local g = re.compile[[
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Tiny <- CmdSeq
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CmdSeq <- (Cmd (SEMICOLON / ErrSemi)) (Cmd (SEMICOLON / ErrSemi))*
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Cmd <- IfCmd / RepeatCmd / ReadCmd / WriteCmd / AssignCmd
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IfCmd <- IF (Exp / ErrExpIf) (THEN / ErrThen) (CmdSeq / ErrCmdSeq1) (ELSE (CmdSeq / ErrCmdSeq2) / '') (END / ErrEnd)
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RepeatCmd <- REPEAT (CmdSeq / ErrCmdSeqRep) (UNTIL / ErrUntil) (Exp / ErrExpRep)
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AssignCmd <- NAME (ASSIGNMENT / ErrAssignOp) (Exp / ErrExpAssign)
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ReadCmd <- READ (NAME / ErrReadName)
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WriteCmd <- WRITE (Exp / ErrWriteExp)
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Exp <- SimpleExp ((LESS / EQUAL) (SimpleExp / ErrSimpExp) / '')
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SimpleExp <- Term ((ADD / SUB) (Term / ErrTerm))*
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Term <- Factor ((MUL / DIV) (Factor / ErrFactor))*
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Factor <- OPENPAR (Exp / ErrExpFac) (CLOSEPAR / ErrClosePar) / NUMBER / NAME
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ErrSemi <- %{errSemi}
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ErrExpIf <- %{errExpIf}
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ErrThen <- %{errThen}
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ErrCmdSeq1 <- %{errCmdSeq1}
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ErrCmdSeq2 <- %{errCmdSeq2}
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ErrEnd <- %{errEnd}
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ErrCmdSeqRep <- %{errCmdSeqRep}
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ErrUntil <- %{errUntil}
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ErrExpRep <- %{errExpRep}
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ErrAssignOp <- %{errAssignOp}
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ErrExpAssign <- %{errExpAssign}
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ErrReadName <- %{errReadName}
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ErrWriteExp <- %{errWriteExp}
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ErrSimpExp <- %{errSimpExp}
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ErrTerm <- %{errTerm}
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ErrFactor <- %{errFactor}
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ErrExpFac <- %{errExpFac}
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ErrClosePar <- %{errClosePar}
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ADD <- Sp '+'
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ASSIGNMENT <- Sp ':='
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CLOSEPAR <- Sp ')'
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DIV <- Sp '/'
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IF <- Sp 'if'
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ELSE <- Sp 'else'
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END <- Sp 'end'
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EQUAL <- Sp '='
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LESS <- Sp '<'
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MUL <- Sp '*'
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NAME <- Sp !RESERVED [a-z]+
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NUMBER <- Sp [0-9]+
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OPENPAR <- Sp '('
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READ <- Sp 'read'
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REPEAT <- Sp 'repeat'
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SEMICOLON <- Sp ';'
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SUB <- Sp '-'
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THEN <- Sp 'then'
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UNTIL <- Sp 'until'
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WRITE <- Sp 'write'
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RESERVED <- (IF / ELSE / END / READ / REPEAT / THEN / UNTIL / WRITE) ![a-z]+
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Sp <- %s*
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]]
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local function mymatch(g, s)
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local r, e, sfail = g:match(s)
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if not r then
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local line, col = re.calcline(s, #s - #sfail)
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local msg = "Error at line " .. line .. " (col " .. col .. "): "
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return r, msg .. terror[e].msg
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end
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return r
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end
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local s = [[
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n := 5;
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f := 1;
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repeat
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f := f + n;
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n := n - 1
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until (n < 1);
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write f;]]
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print(mymatch(g, s))
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s = [[
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n := 5;
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f := 1;
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repeat
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f := f + n;
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n := n - 1;
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until (n < 1);
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read ;]]
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print(mymatch(g, s))
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s = [[
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if a < 1 then
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b := 2;
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else
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b := 3;]]
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print(mymatch(g, s))
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s = [[
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n := 5;
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f := 1;
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repeat
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f := f + n;
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n := n - 1;
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untill (n < 1);
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]]
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print(mymatch(g, s))
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s = [[
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n := 5;
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f := 1;
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repeat
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f := f + n;
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n := n - 1;
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3 (n < 1);
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]]
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print(mymatch(g, s))
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print(mymatch(g, "a : 2"))
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print(mymatch(g, "a := (2"))
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