Decimal Parameter unable to hold a signed number

[curious-ninja]

Hello,
While working on a custom module for bettercap, I noticed that the DecimalParameter is unable to hold a signed number.

The relevant code from my module:

if err, mod.battcurrent = mod.DecParam("health.battcurrent"); err != nil {
		return err
	}

Results in a validation error.

See:

bettercap/session/module_param.go

Line 62 in 568c166

return NewModuleParameter(name, def_value, FLOAT, "^[\\d]+(\\.\\d+)?$", desc)

I changed the line to:

return NewModuleParameter(name, def_value, FLOAT, `^[\-\+]?[\d]+(\.\d+)?$`, desc)

Environment

• Bettercap version: 2.31.0

• OS version and architecture: ARM 64 (Kali Linux on RPi4)

• Go version: 1.16.3

• Command line arguments you are using:
  sudo bettercap -caplet http-ui -iface wlan0 -debug

• Caplet code you are using or the interactive session commands.
  http-ui caplet

• Full debug output while reproducing the issue ( bettercap -debug ... ).
  wlan0 » [16:21:53] [sys.log] [err] Parameter health.battcurrent not valid: '-0.01' does not match rule '^[\d]+(.\d+)?$'.

Steps to Reproduce

See above

Expected behavior:
Negative number gets assigned to the float/decimal parameter.

Actual behavior:
Reg exp validation error for negative float/decimal parameter.

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