From c127e2898e6f63bdf0733b8c6b636ad9bb32b51c Mon Sep 17 00:00:00 2001 From: PeterBocan Date: Mon, 1 Jul 2019 16:45:01 +0200 Subject: [PATCH 1/3] Added a constructor to structs --- examples/structs/structs.go | 13 ++++++++++ examples/structs/structs.hash | 4 +-- examples/structs/structs.sh | 1 + public/structs | 47 +++++++++++++++++++++++++++++++++-- 4 files changed, 61 insertions(+), 4 deletions(-) diff --git a/examples/structs/structs.go b/examples/structs/structs.go index 6cf5629..21584a2 100644 --- a/examples/structs/structs.go +++ b/examples/structs/structs.go @@ -12,6 +12,16 @@ type person struct { age int } +// A de facto constructor of type `person`. +func NewPerson(name string) *person { + + // You can safely return a pointer to local variable + // as a local variable will survive the scope of the function. + p := person{name: name} + p.age = 42 + return &p +} + func main() { // This syntax creates a new struct. @@ -38,4 +48,7 @@ func main() { // Structs are mutable. sp.age = 51 fmt.Println(sp.age) + + // Call our constructor + fmt.Println(NewPerson("Jon")) } diff --git a/examples/structs/structs.hash b/examples/structs/structs.hash index 2c0e37f..a1194e9 100644 --- a/examples/structs/structs.hash +++ b/examples/structs/structs.hash @@ -1,2 +1,2 @@ -49cad39331ee5e9fb8d8dad99d3aff7f18a4e6d0 -XMZpGsF4sWM +71e8ecdcf8c8fbddbb250ada5bbe8659b68d5229 +nHvnHAGTYHq diff --git a/examples/structs/structs.sh b/examples/structs/structs.sh index 6d82fa0..f0d6025 100644 --- a/examples/structs/structs.sh +++ b/examples/structs/structs.sh @@ -6,3 +6,4 @@ $ go run structs.go Sean 50 51 +&{Jon 42} \ No newline at end of file diff --git a/public/structs b/public/structs index 31c03d0..22fd85f 100644 --- a/public/structs +++ b/public/structs @@ -29,7 +29,7 @@ records.

- + 
package main
@@ -66,6 +66,36 @@ records.

           
         
         
+        
+          
+            
A de facto constructor of type person.

+
+          
+          
+            
+            
func NewPerson(name string) *person {
+

+
+          
+        
+        
+        
+          
+            
You can safely return a pointer to local variable
+as a local variable will survive the scope of the function.

+
+          
+          
+            
+            
    p := person{name: name}
+    p.age = 42
+    return &p
+}
+

+
+          
+        
+        
         
           
             
@@ -164,10 +194,23 @@ pointers are automatically dereferenced.

             
Structs are mutable.

 
           
-          
+          
             
             
    sp.age = 51
     fmt.Println(sp.age)
+

+
+          
+        
+        
+        
+          
+            
Call our constructor

+
+          
+          
+            
+            
    fmt.Println(NewPerson("Jon"))
 }
 

 

From 615d5e2eb460851838448c5b1bd7a768b79c9ab9 Mon Sep 17 00:00:00 2001
From: PeterBocan 
Date: Tue, 2 Jul 2019 15:46:54 +0200
Subject: [PATCH 2/3] Struct allocation fixes.

---
 examples/structs/structs.go   |  8 ++++----
 examples/structs/structs.hash |  4 ++--
 public/structs                | 24 ++++++++++++++++++------
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/examples/structs/structs.go b/examples/structs/structs.go
index 21584a2..e2546fe 100644
--- a/examples/structs/structs.go
+++ b/examples/structs/structs.go
@@ -12,9 +12,8 @@ type person struct {
 	age  int
 }
 
-// A de facto constructor of type `person`.
+// NewPerson constructs a new person struct with the given name
 func NewPerson(name string) *person {
-
 	// You can safely return a pointer to local variable
 	// as a local variable will survive the scope of the function.
 	p := person{name: name}
@@ -36,6 +35,9 @@ func main() {
 	// An `&` prefix yields a pointer to the struct.
 	fmt.Println(&person{name: "Ann", age: 40})
 
+	// It's idiomatic to encapsulate new struct creation in constructor functions
+	fmt.Println(NewPerson("Jon"))
+
 	// Access struct fields with a dot.
 	s := person{name: "Sean", age: 50}
 	fmt.Println(s.name)
@@ -49,6 +51,4 @@ func main() {
 	sp.age = 51
 	fmt.Println(sp.age)
 
-	// Call our constructor
-	fmt.Println(NewPerson("Jon"))
 }
diff --git a/examples/structs/structs.hash b/examples/structs/structs.hash
index a1194e9..50e4d67 100644
--- a/examples/structs/structs.hash
+++ b/examples/structs/structs.hash
@@ -1,2 +1,2 @@
-71e8ecdcf8c8fbddbb250ada5bbe8659b68d5229
-nHvnHAGTYHq
+cd504951e9f8504c159a66714b04bfda0629e58c
+ezfE4eojTS7
diff --git a/public/structs b/public/structs
index 22fd85f..0ea36aa 100644
--- a/public/structs
+++ b/public/structs
@@ -29,7 +29,7 @@ records.

             
           
           
-            
+            
               
             
             
package main
@@ -68,7 +68,7 @@ records.

         
         
           
-            
A de facto constructor of type person.

+            
NewPerson constructs a new person struct with the given name

 
           
           
@@ -160,6 +160,19 @@ as a local variable will survive the scope of the function.

           
         
         
+        
+          
+            
It’s idiomatic to encapsulate new struct creation in constructor functions

+
+          
+          
+            
+            
    fmt.Println(NewPerson("Jon"))
+

+
+          
+        
+        
         
           
             
Access struct fields with a dot.

@@ -205,13 +218,11 @@ pointers are automatically dereferenced.

         
         
           
-            
Call our constructor

-
+            
           
           
             
-            
    fmt.Println(NewPerson("Jon"))
-}
+            
}
 

 
           
@@ -235,6 +246,7 @@ pointers are automatically dereferenced.

 Sean
 50
 51
+&{Jon 42}
 

 
           

From c22f42f03cb1511c24e573374390ec261d6e2704 Mon Sep 17 00:00:00 2001
From: PeterBocan 
Date: Tue, 2 Jul 2019 16:30:42 +0200
Subject: [PATCH 3/3] Remove extra whitespace

---
 examples/structs/structs.go | 1 -
 1 file changed, 1 deletion(-)

diff --git a/examples/structs/structs.go b/examples/structs/structs.go
index e2546fe..384b57c 100644
--- a/examples/structs/structs.go
+++ b/examples/structs/structs.go
@@ -50,5 +50,4 @@ func main() {
 	// Structs are mutable.
 	sp.age = 51
 	fmt.Println(sp.age)
-
 }