1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163
|
---
title: Either/or schema validation of different, equally valid different kinds of YAML
---
StrictYAML can be directed to parse two different elements or
blocks of YAML.
If the first thing does not parse correctly, it attempts to
parse the second. If the second does not parse correctly,
it raises an exception.
```python
from strictyaml import Map, Seq, Bool, Int, Str, YAMLValidationError, load
from ensure import Ensure
schema = Str() | Map({"a": Bool() | Int()})
```
Boolean first choice true:
```yaml
a: yes
```
```python
Ensure(load(yaml_snippet, schema)).equals({"a": True})
```
Boolean first choice false:
```yaml
a: no
```
```python
Ensure(load(yaml_snippet, schema)).equals({"a": False})
```
Int second choice:
```yaml
a: 5
```
```python
Ensure(load(yaml_snippet, schema)).equals({"a": 5})
```
Invalid not bool or int:
```yaml
a: A
```
```python
load(yaml_snippet, schema)
```
```python
strictyaml.exceptions.YAMLValidationError:
when expecting an integer
found arbitrary text
in "<unicode string>", line 1, column 1:
a: A
^ (line: 1)
```
Invalid combinations of more than one map:
```yaml
a: x
```
```python
load(yaml_snippet, Map({"a": Str()}) | Map({"b": Str()}))
```
```python
strictyaml.exceptions.InvalidValidatorError:
You tried to Or ('|') together 2 Map validators. Try using revalidation instead.
```
Invalid combinations of more than one seq:
```yaml
- 1
- 2
```
```python
load(yaml_snippet, Seq(Int()) | Seq(Str()))
```
```python
strictyaml.exceptions.InvalidValidatorError:
You tried to Or ('|') together 2 Seq validators. Try using revalidation instead.
```
Change item after validated:
```yaml
a: yes
```
```python
yaml = load(yaml_snippet, schema)
yaml['a'] = 5
assert yaml['a'] == 5
```
!!! note "Executable specification"
Documentation automatically generated from
<a href="https://github.com/crdoconnor/strictyaml/blob/master/hitch/story/or.story">or.story
storytests.
|