使用 YAML.mapping 解析复杂的 YAML 结构

Question

我在 YAML 中有这样的复杂结构

yaml = <<-STR
'Tunisie Telecom':
regex: 'StarTrail TT[);/ ]'
device: 'smartphone'
model: 'StarTrail'
Palm:
regex: '(?:Pre|Pixi)/(d+).(d+)|Palm|Treo|Xiino'
device: 'smartphone'
models:
- regex: '((?:Pre|Pixi))/(d+.d+)'
model: '$1 $2'
- regex: 'Palm(?:[ -])?((?!OS|Source|scape)[a-z0-9]+)'
model: '$1'
STR

我尝试使用 YAML.mapping 解析它：

class Mobile
YAML.mapping(
name: Hash(String, Hash(String, String))
)
end
puts Mobile.from_yaml(yaml)

并得到解析异常：

Missing yaml attribute: name at line 1, column 1 (YAML::ParseException)
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/yaml/nodes/nodes.cr:30:9 in 'raise'
from mobiles_mapping.cr:0:3 in 'initialize'
from mobiles_mapping.cr:20:3 in 'new'
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/yaml/from_yaml.cr:2:3 in 'from_yaml'
from mobiles_mapping.cr:25:1 in '__crystal_main'
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/crystal/main.cr:11:3 in '_crystal_main'
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/crystal/main.cr:112:5 in 'main_user_code'
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/crystal/main.cr:101:7 in 'main'
from /usr/local/Cellar/crystal-lang/0.24.2_1/src/crystal/main.cr:135:3 in 'main'

但是如果我尝试使用 YAML.parse 解析：

{"Tunisie Telecom" => {"regex" => "StarTrail TT[);/ ]", "device" => "smartphone", "model" => "StarTrail"}, "Palm" => {"regex" => "(?:Pre|Pixi)/(d+).(d+)|Palm|Treo|Xiino", "device" => "smartphone", "models" => [{"regex" => "((?:Pre|Pixi))/(d+.d+)", "model" => "$1 $2"}, {"regex" => "Palm(?:[ -])?((?!OS|Source|scape)[a-z0-9]+)", "model" => "$1"}]}}

我的错误是什么？

在线示例：https://play.crystal-lang.org/#/r/41yk

UPD：我明白了：宏找不到键"名称"，但是如何在没有键=> val的情况下解析，就像我只有键的情况一样？

Answer 1

你得到的是一个Hash(String, Mobile)，其中Mobile类似于

class Mobile
YAML.mapping({
regex: String,
device: String,
model: String?,
models: Array(...)?
})
end

因此，要解析，您应该调用Hash(String, Mobile).from_yaml。

如果您的 YAML 是：

name:
'Tunisie Telecom':
regex: 'StarTrail TT[);/ ]'
device: 'smartphone'
model: 'StarTrail'
Palm:
regex: '(?:Pre|Pixi)/(d+).(d+)|Palm|Treo|Xiino'
device: 'smartphone'
models:
- regex: '((?:Pre|Pixi))/(d+.d+)'
model: '$1 $2'
- regex: 'Palm(?:[ -])?((?!OS|Source|scape)[a-z0-9]+)'
model: '$1'