Numbers in scientific notation without dot are parsed as string

Hi,

it appears that PyYAML requires a dot in the mantissa as well as a sign in the exponent in order to parse numbers in scientific notation as numbers and otherwise parses them as string:

>>> import yaml
>>> yaml.safe_load('1e+10')
'1e+10'
>>> yaml.safe_load('1.e+10')
10000000000.0
>>> yaml.safe_load('1.0e10')
'1.0e10'

According to YAML 1.2 spec the dot is optional as in JSON:

Either 0, .inf, -.inf, .nan, or scientific notation matching the regular expression -? [1-9] ( \. [0-9]* [1-9] )? ( e [-+] [1-9] [0-9]* )?.

Furthermore, JSON makes even the sign in the exponent optional: https://www.json.org/number.gif

Since YAML 1.2 aspires to be a superset of JSON, I believe it should make the sign optional as well.

Others than ran into similar problems:

https://stackoverflow.com/questions/30458977/yaml-loads-5e-6-as-string-and-not-a-number

Best, Thomas

[AlexanderNaehring]

Issue is still present, I use the fix found on Stackoverflow, manually adding the new implicit resolver.

[ischoegl]

For anyone running into similar issues, the derived package ruamel.yaml resolves issues like the one stated above.