Removing example "recovery.lua"

1 files changed, 0 insertions, 134 deletions

diff --git a/examples/recovery.lua b/examples/recovery.lua
deleted file mode 100644
index bb17b54..0000000
--- a/examples/recovery.lua
+++ /dev/null
@@ -1,134 +0,0 @@
-local lpeg = require"lpeglabelrec"
-
-local R, S, P, V = lpeg.R, lpeg.S, lpeg.P, lpeg.V
-local C, Cc, Ct, Cmt = lpeg.C, lpeg.Cc, lpeg.Ct, lpeg.Cmt
-local T, Lc = lpeg.T, lpeg.Lc
-
--- The `labels` table contains the list of labels that we will be using
--- as well as the corresponding error message for each label, which will
--- be used in our error reporting later on.
-local labels = {
-  {"NoExp",     "no expression found"},
-  {"Extra",     "extra characters found after the expression"},
-  {"ExpTerm",   "expected a term after the operator"},
-  {"ExpExp",    "expected an expression after the parenthesis"},
-  {"MisClose",  "missing a closing ')' after the expression"},
-}
-
--- The `labelindex` function gives us the index of a label in the
--- `labels` table, which serves as the integer representation of the label.
--- We need this because LPegLabel requires us to use integers for the labels.
-local function labelindex(labname)
-  for i, elem in ipairs(labels) do
-    if elem[1] == labname then
-      return i
-    end
-  end
-  error("could not find label: " .. labname)
-end
-
--- The `errors` table will hold the list of errors recorded during parsing
-local errors = {}
-
--- The `expect` function takes a pattern and a label and returns a pattern
--- that throws the specified label if the original pattern fails to match.
--- Before throwing the label, it records the label to be thrown along with
--- the position of the failure (index in input string) into the `errors` table.
-local function expect(patt, labname)
-  local i = labelindex(labname)
-  function recorderror(input, pos)
-    table.insert(errors, {i, pos})
-    return true
-  end
-  return patt + Cmt("", recorderror) * T(i)
-end
-
-local num = R("09")^1 / tonumber
-local op = S("+-*/")
-
--- The `compute` function takes an alternating list of numbers and
--- operators and computes the result of applying the operations
--- to the numbers in a left to right order (no operator precedence).
-local function compute(tokens)
-  local result = tokens[1]
-  for i = 2, #tokens, 2 do
-    if tokens[i] == '+' then
-      result = result + tokens[i+1]
-    elseif tokens[i] == '-' then
-      result = result - tokens[i+1]
-    elseif tokens[i] == '*' then
-      result = result * tokens[i+1]
-    elseif tokens[i] == '/' then
-      result = result / tokens[i+1]
-    else
-      error('unknown operation: ' .. tokens[i])
-    end
-  end
-  return result
-end
-
--- Our grammar is a simple arithmetic expression of integers that
--- does not take operator precedence into account but allows grouping
--- via parenthesis. We have incorporated some error recovery startegies
--- to our grammar so that it may resume parsing even after encountering
--- an error, which allows us to report more errors.
-local g = P {
-  "Exp",
-  Exp = Ct(V"Term" * (C(op) * V"OpRecov")^0) / compute;
-  -- `OpRecov` handles missing terms/operands by returning a dummy (zero).
-  OpRecov = Lc(V"Operand", Cc(0), labelindex("ExpTerm"));
-  Operand = expect(V"Term", "ExpTerm");
-  Term = num + V"Group";
-  -- `Group` handles missing closing parenthesis by simply ignoring it.
-  -- Like all the others, the error is still recorded of course.
-  Group = "(" * V"InnerExp" * Lc(expect(")", "MisClose"), P"", labelindex("MisClose"));
-  -- `InnerExp` handles missing expressions by skipping to the next closing
-  -- parenthesis. A dummy (zero) is returned in place of the expression.
-  InnerExp = Lc(expect(V"Exp", "ExpExp"), (P(1) - ")")^0 * Cc(0), labelindex("ExpExp"));
-}
-
-g = expect(g, "NoExp") * expect(-P(1), "Extra")
-
--- The `eval` function takes an input string to match against the grammar
--- we've just defined. If the input string matches, then the result of the
--- computation is returned, otherwise we return the error messages and
--- positions of all the failures encountered.
-local function eval(input)
-  local result, label, suffix = g:match(input)
-  if #errors == 0 then
-    return result
-  else
-    local out = {}
-    for i, err in ipairs(errors) do
-      local pos = err[2]
-      local msg = labels[err[1]][2]
-      table.insert(out, "syntax error: " .. msg .. " (at index " .. pos .. ")")
-    end
-    errors = {}
-    return nil, table.concat(out, "\n")
-  end
-end
-
-print(eval "98-76*(54/32)")
---> 37.125
-
-print(eval "(1+1-1*2/2")
---> syntax error: missing a closing ')' after the expression (at index 11)
-
-print(eval "(1+)-1*(2/2)")
---> syntax error: expected a term after the operator (at index 4)
-
-print(eval "(1+1)-1*(/2)")
---> syntax error: expected an expression after the parenthesis (at index 10)
-
-print(eval "1+(1-(1*2))/2x")
---> syntax error: extra chracters found after the expression (at index 14)
-
-print(eval "-1+(1-(1*2))/2")
---> syntax error: no expression found (at index 1)
-
-print(eval "(1+1-1*(2/2+)-():")
---> syntax error: expected a term after the operator (at index 13)
---> syntax error: expected an expression after the parenthesis (at index 16)
---> syntax error: missing a closing ')' after the expression (at index 17)
---> syntax error: extra characters found after the expression (at index 17)