Merge pull request #809 from darkowlzz/version-doc

docs: Gopkg.toml.md version

Author: darkowlzz

FAQ.md

@@ -83,6 +83,9 @@ Here are some suggestions for when you could use `dep` or `go get`:
 * Use `required` to explicitly add a dependency that is not imported directly or transitively, for example a development package used for code generation.
 * Use `ignored` to ignore a package and any of that package's unique dependencies.
 
+Refer [Gopkg.toml](https://github.com/golang/dep/blob/master/docs/Gopkg.toml.md)
+for detailed definitions of the above terms.
+
 ## How do I constrain a transitive dependency's version?
 First, if you're wondering about this because you're trying to keep the version
 of the transitive dependency from changing, then you're working against `dep`'s
@@ -171,20 +174,8 @@ Only your project's directly imported dependencies are affected by a `constraint
 in the manifest. Transitive dependencies are unaffected.
 
 Use an `override` entry for transitive dependencies.
-
-By default, when you specify a version without an operator, such as `~` or `=`,
-`dep` automatically adds a caret operator, `^`. The caret operator pins the
-left-most non-zero digit in the version. For example:
-```
-^1.2.3 means 1.2.3 <= X < 2.0.0
-^0.2.3 means 0.2.3 <= X < 0.3.0
-^0.0.3 means 0.0.3 <= X < 0.1.0
-```
-
-To pin a version of direct dependency in manifest, prefix the version with `=`.
-For example:
 ```
-[[constraint]]
+[[override]]
   name = "github.com/pkg/errors"
   version = "=0.8.0"
 ```

docs/Gopkg.toml.md

@@ -71,6 +71,33 @@ An `override` has the same structure as a `constraint` declaration, but supersed
   system2-data = "value that is used by another system"
 ```
 
+## `version`
+
+`version` is a property of `constraint`s and `override`s. It is used to specify
+version constraint of a specific dependency.
+
+Internally, dep uses [Masterminds/semver](https://github.com/Masterminds/semver)
+to work with semver versioning.
+
+`~` and `=` operators can be used with the versions. When a version is specified
+without any operator, `dep` automatically adds a caret operator, `^`. The caret
+operator pins the left-most non-zero digit in the version. For example:
+```
+^1.2.3 means 1.2.3 <= X < 2.0.0
+^0.2.3 means 0.2.3 <= X < 0.3.0
+^0.0.3 means 0.0.3 <= X < 0.1.0
+```
+
+To pin a version of direct dependency in manifest, prefix the version with `=`.
+For example:
+```
+[[constraint]]
+  name = "github.com/pkg/errors"
+  version = "=0.8.0"
+```
+
+[Why is dep ignoring a version constraint in the manifest?](https://github.com/golang/dep/blob/master/FAQ.md#why-is-dep-ignoring-a-version-constraint-in-the-manifest)
+
 # Example
 
 Here's an example of a sample Gopkg.toml with most of the elements
@@ -102,4 +129,4 @@ codename = "foo"
 
   [metadata]
   propertyX = "valueX"
-```
+```