fix(core): Error on excess unparsable input on measurements and lengths (#2260)

Author: alerque

types/length.lua

@@ -49,7 +49,9 @@ function length:_init (spec, stretch, shrink)
       if type(amount) == "number" then
          self:_init(amount)
       else
-         local parsed = SILE.parserBits.length:match(spec)
+         local input = pl.stringx.strip(spec)
+         local length_only_parser = SILE.parserBits.length * -1
+         local parsed = length_only_parser:match(input)
          if not parsed then
             SU.error("Could not parse length '" .. spec .. "'")
          end

types/measurement.lua

@@ -78,7 +78,9 @@ function measurement:_init (amount, unit)
    elseif type(tonumber(amount)) == "number" then
       self.amount = tonumber(amount)
    elseif type(amount) == "string" then
-      local parsed = SILE.parserBits.measurement:match(amount)
+      local input = pl.stringx.strip(amount)
+      local measurement_only_parser = SILE.parserBits.measurement * -1
+      local parsed = measurement_only_parser:match(input)
       if not parsed then
          SU.error("Could not parse measurement '" .. amount .. "'")
       end

types/unit.lua

@@ -15,7 +15,9 @@ setmetatable(unittypes, {
       local def = SU.required(spec, "definition", "registering unit " .. unit)
       local relative = SU.boolean(spec.relative, false)
       if type(def) == "string" then
-         local parsed = bits.measurement:match(def)
+         local input = pl.stringx.strip(def)
+         local measurement_only_parser = bits.measurement * -1
+         local parsed = measurement_only_parser:match(input)
          if not parsed then
             SU.error("Could not parse unit definition '" .. def .. "'")
          end