Sway Ref: Style guide unused variables

docs/reference/src/SUMMARY.md

@@ -71,6 +71,7 @@
   - [Pattern Matching](./documentation/language/style-guide/pattern-matching.md)
   - [Comments](./documentation/language/style-guide/comments.md)
   - [Getter Functions](./documentation/language/style-guide/getters.md)
+  - [Unused Variables](./documentation/language/style-guide/unused-variables.md)
 
 ## Common Operations
 

docs/reference/src/code/Forc.lock

@@ -1,27 +1,27 @@
 [[package]]
 name = 'annotation_style'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'annotations'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'arrays'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'assertions'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'asset_operations'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'associated-consts'
@@ -30,30 +30,30 @@ source = 'member'
 [[package]]
 name = 'booleans'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'bytes'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'call'
 source = 'member'
 dependencies = [
     'contract_interface',
-    'std',
+    'std path+from-root-0F28276288D2432C',
 ]
 
 [[package]]
 name = 'call_data'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'comments'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'constants'
@@ -62,184 +62,203 @@ source = 'member'
 [[package]]
 name = 'contract_interface'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'control_flow'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'core'
 source = 'path+from-root-0F28276288D2432C'
 
+[[package]]
+name = 'core'
+source = 'path+from-root-D62A8C57DD8D2801'
+
 [[package]]
 name = 'counter'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'empty_storage_init'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'enum-advanced'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'enum_style'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'enums'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'fizzbuzz'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'functions'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
+
+[[package]]
+name = 'getters'
+source = 'member'
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'hashing'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'interface'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'letter_casing'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'logging'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'my_lib'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'my_library'
 source = 'member'
 dependencies = [
     'my_other_library',
-    'std',
+    'std path+from-root-0F28276288D2432C',
 ]
 
 [[package]]
 name = 'my_other_library'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'namespace'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'numerics'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'ownership'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'reading_writing_to_storage'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'simple_predicate'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'simple_script'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
+
+[[package]]
+name = 'std'
+source = 'git+https://github.com/fuellabs/sway?tag=v0.40.1#48104d0bde0d343154a5bc39a310092532883235'
+dependencies = ['core path+from-root-D62A8C57DD8D2801']
 
 [[package]]
 name = 'std'
 source = 'path+from-root-0F28276288D2432C'
-dependencies = ['core']
+dependencies = ['core path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'storage_init'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'storage_map'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'storage_vec'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'store_get'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'string_issue'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'strings'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'struct_shorthand'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'structs'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'tuples'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
+
+[[package]]
+name = 'unused_variables'
+source = 'member'
+dependencies = ['std git+https://github.com/fuellabs/sway?tag=v0.40.1#48104d0bde0d343154a5bc39a310092532883235']
 
 [[package]]
 name = 'variables'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']
 
 [[package]]
 name = 'wallet'
 source = 'member'
 dependencies = [
     'interface',
-    'std',
+    'std path+from-root-0F28276288D2432C',
 ]
 
 [[package]]
 name = 'wallet_example'
 source = 'member'
-dependencies = ['std']
+dependencies = ['std path+from-root-0F28276288D2432C']

docs/reference/src/code/Forc.toml

@@ -26,8 +26,10 @@ members = [
   "language/program-types/scripts/simple_script",
   "language/style-guide/annotation_style",
   "language/style-guide/enum_style",
+  "language/style-guide/getters",
   "language/style-guide/letter_casing",
   "language/style-guide/struct_shorthand",
+  "language/style-guide/unused_variables",
   "language/traits/associated-consts",
   "language/variables",
   "misc/advanced-concepts/enum_advanced",

docs/reference/src/code/language/style-guide/unused_variables/.gitignore

@@ -0,0 +1,2 @@
+out
+target

docs/reference/src/code/language/style-guide/unused_variables/Forc.toml

@@ -0,0 +1,7 @@
+[project]
+authors = ["Fuel Labs <[email protected]>"]
+entry = "lib.sw"
+license = "Apache-2.0"
+name = "unused_variables"
+
+[dependencies]

docs/reference/src/code/language/style-guide/unused_variables/src/lib.sw

@@ -0,0 +1,34 @@
+library;
+
+#[allow(dead_code)]
+fn call() -> (u64, u64) {
+    // Random data for demonstration in the subsequent functions
+    (1, 2)
+}
+
+#[allow(dead_code)]
+// ANCHOR: unused_variable
+fn unused_variable() -> u64 {
+    let (timestamp, deposit_amount) = call();
+
+    deposit_amount
+}
+// ANCHOR_END: unused_variable
+
+#[allow(dead_code)]
+// ANCHOR: named_unused_variable
+fn named_unused_variable() -> u64 {
+    let (_timestamp, deposit_amount) = call();
+
+    deposit_amount
+}
+// ANCHOR_END: named_unused_variable
+
+#[allow(dead_code)]
+// ANCHOR: nameless_variable
+fn nameless_variable() -> u64 {
+    let (_, deposit_amount) = call();
+
+    deposit_amount
+}
+// ANCHOR_END: nameless_variable

docs/reference/src/documentation/language/style-guide/unused-variables.md

@@ -0,0 +1,23 @@
+# Unused Variables
+
+A good practice is naming variables appropriately; however, variables may be unused at times such as the `timestamp` from the `call()`.
+
+```sway
+{{#include ../../../code/language/style-guide/unused_variables/src/lib.sw:unused_variable}}
+```
+
+## Named
+
+We may preserve the name to provide context to the reader by prepending the variable with `_`.
+
+```sway
+{{#include ../../../code/language/style-guide/unused_variables/src/lib.sw:named_unused_variable}}
+```
+
+## Nameless
+
+We may discard the context and the value by assigning it to `_`.
+
+```sway
+{{#include ../../../code/language/style-guide/unused_variables/src/lib.sw:nameless_variable}}
+```