From ef56723060c8c1e8723e22886a3c556aca146bb7 Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Wed, 11 May 2016 15:47:05 -0400 Subject: Created scoping section --- docs/control-structures.rst | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 2d959d1d..e26286d0 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -142,6 +142,12 @@ Assigning *to* a state variable always creates an independent copy. On the other .. index:: ! exception, ! throw +Scoping +======= + +.. index:: ! scoping + + Exceptions ========== -- cgit v1.2.3 From 08b7d4aebe0c576d06bb9c8c73fdd21a2044ccb8 Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Wed, 11 May 2016 17:02:28 -0400 Subject: Changed the title --- docs/control-structures.rst | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index e26286d0..77fbee52 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -142,11 +142,10 @@ Assigning *to* a state variable always creates an independent copy. On the other .. index:: ! exception, ! throw -Scoping -======= - -.. index:: ! scoping +Scoping and Declarations +======================== +.. index:: ! scoping, ! declarations Exceptions ========== -- cgit v1.2.3 From 52a8d7b3f5cbf3538d0c4e9f60446ebb59fb72ff Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Wed, 11 May 2016 17:07:25 -0400 Subject: Added content --- docs/control-structures.rst | 51 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 77fbee52..0ad1c591 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -147,6 +147,57 @@ Scoping and Declarations .. index:: ! scoping, ! declarations +In Solidity, a variable declared anywhere within a function will be in scope for the *entire function*, regardless of where it is declared. +This is in contrast to many languages where variables are only scoped where they are declared until the end of the semantic block. +As a result, the following code is illegal and cause the compiler to throw an error, `Identifier already declared.`:: + + contract ScopingErrors { + function scoping() { + uint i = 0; + + while (i++ < 1) { + uint same1 = 0; + } + + while (i++ < 2) { + uint same1 = 0;// Illegal, second declaration of same1 + } + } + + function minimalScoping() { + { + uint same2 = 0; + } + + { + uint same2 = 0;// Illegal, second declaration of same2 + } + } + + function forLoopScoping() { + for (uint same3 = 0; same3 < 1; same3++) { + } + + for (uint same3 = 0; same3 < 1; same3++) {// Illegal, second declaration of same3 + } + } + } + +In addition to this, if a variable is declared, it will be initialized at the beginning of the function to its default value. +As a result, the following code is legal, despite being poorly written.:: + + function foo() returns (uint) { + uint bar = 5; + // baz is implicitly initialized as 0 + if (true) { + bar += baz; + } + else { + uint baz = 10;// never executes + } + return bar;// returns 5 + } + Exceptions ========== -- cgit v1.2.3 From e60a17379e350eed72c9a0b6c4c100a9f08ba215 Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Thu, 12 May 2016 09:48:56 -0400 Subject: Removed trailing spaces --- docs/control-structures.rst | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 0ad1c591..86f54453 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -154,21 +154,21 @@ As a result, the following code is illegal and cause the compiler to throw an er contract ScopingErrors { function scoping() { uint i = 0; - + while (i++ < 1) { uint same1 = 0; } - + while (i++ < 2) { uint same1 = 0;// Illegal, second declaration of same1 } } - + function minimalScoping() { { uint same2 = 0; } - + { uint same2 = 0;// Illegal, second declaration of same2 } -- cgit v1.2.3 From 50eb3b8f8f8679e4508ae0da741af65f8cd4a263 Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Thu, 12 May 2016 09:49:49 -0400 Subject: Moved comment to more logical place --- docs/control-structures.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 86f54453..3e766b5c 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -187,8 +187,8 @@ In addition to this, if a variable is declared, it will be initialized at the be As a result, the following code is legal, despite being poorly written.:: function foo() returns (uint) { - uint bar = 5; // baz is implicitly initialized as 0 + uint bar = 5; if (true) { bar += baz; } -- cgit v1.2.3 From 7b6fd013a473e93f1f9381de19e83c06697af10c Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Thu, 12 May 2016 09:59:29 -0400 Subject: Added origin of scoping rules --- docs/control-structures.rst | 1 + 1 file changed, 1 insertion(+) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 3e766b5c..0e74c589 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -148,6 +148,7 @@ Scoping and Declarations .. index:: ! scoping, ! declarations In Solidity, a variable declared anywhere within a function will be in scope for the *entire function*, regardless of where it is declared. +This happens because Solidity inherits its scoping rules from JavaScript. This is in contrast to many languages where variables are only scoped where they are declared until the end of the semantic block. As a result, the following code is illegal and cause the compiler to throw an error, `Identifier already declared.`:: -- cgit v1.2.3 From 20cec07b466b99893fecfb82a0f0e35acfb6bdda Mon Sep 17 00:00:00 2001 From: Denton Liu Date: Thu, 12 May 2016 13:25:00 -0400 Subject: Removed unnecessary period --- docs/control-structures.rst | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'docs') diff --git a/docs/control-structures.rst b/docs/control-structures.rst index 0e74c589..b24909a6 100644 --- a/docs/control-structures.rst +++ b/docs/control-structures.rst @@ -150,7 +150,7 @@ Scoping and Declarations In Solidity, a variable declared anywhere within a function will be in scope for the *entire function*, regardless of where it is declared. This happens because Solidity inherits its scoping rules from JavaScript. This is in contrast to many languages where variables are only scoped where they are declared until the end of the semantic block. -As a result, the following code is illegal and cause the compiler to throw an error, `Identifier already declared.`:: +As a result, the following code is illegal and cause the compiler to throw an error, `Identifier already declared`:: contract ScopingErrors { function scoping() { @@ -185,7 +185,7 @@ As a result, the following code is illegal and cause the compiler to throw an er } In addition to this, if a variable is declared, it will be initialized at the beginning of the function to its default value. -As a result, the following code is legal, despite being poorly written.:: +As a result, the following code is legal, despite being poorly written:: function foo() returns (uint) { // baz is implicitly initialized as 0 -- cgit v1.2.3