[PATCH 0/4] docs: spec: constant initialization and assignments

[PATCH 0/4] docs: spec: constant initialization and assignments

[ricardo_kagawa]

From: Ricardo Kagawa <ricardo_kagawa@disroot.org>

For this patchset I'm assuming that:

- We agreed constants should be initialized immediately, and that this
  should be validated in syntax, rather than during semantic analysis;
- We agreed that chained assignments and related constructs were indeed
  not desired, and can be safely removed.

The last commit in the set is optional, and should be removed or
reverted depending on when the definitions of binary operators land. You
may choose to not include it regardless, but I'm not a great fan of
specifications that are not self-consistent.

-- >8 --

This patchset includes changes suggested in a superseded patchset:

- Refactoring and renaming non-terminals in the grammar specification
  for better clarity in definitions related to variable declarations
  and assignments;
- Removing the ability to declare uninitialized constant variables;
- Removing the ability to use assignments as expressions;
    - This also removes the ability to use chained assignments; and
    - This also removes the ability to use assignments inside
      conditional clauses of future statements.
- Temporarily removes assignment operators that still don't have their
  corresponding binary operators defined. Please remove or revert this
  last commit if those missing definitions are incorporated before this
  patchset. Otherwise, revert it after they are applied.

Ricardo Kagawa (4):
  docs: spec: refactor grammar specification
  docs: spec: immediate constant initialization
  docs: spec: remove assignment as expression
  docs: spec: postpone assignment operators

 docs/pages/language-specification.md | 36 +++++++++++-----------------
 1 file changed, 14 insertions(+), 22 deletions(-)

-- 
2.44.0

[PATCH 1/4] docs: spec: refactor grammar specification

[ricardo_kagawa]

From: Ricardo Kagawa <ricardo_kagawa@disroot.org>

- Moved statements common to the translation unit and function bodies to
  their own non-terminal.
- Moved some non-terminals from the "Statements" section to the
  "Functions" section, as there will be some statements that are
  function-body specific, some that are translation-unit specific, and
  some that are common to both.
- Renamed "assign" to "assignment", for better wording.
- Renamed <integer> to <integer-literal> to make it more explicit that
  this symbol represents a literal value.
- Replaced <identifier> in <expression> for <variable-name> to make it
  more explicit that it must refer to a variable, and not just any
  identifier.

Signed-off-by: Ricardo Kagawa <ricardo_kagawa@disroot.org>
---
 docs/pages/language-specification.md | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/docs/pages/language-specification.md b/docs/pages/language-specification.md
index 4d0eb36..9f4383d 100644
--- a/docs/pages/language-specification.md
+++ b/docs/pages/language-specification.md
@@ -24,10 +24,11 @@ language.
 (* Entry Point *)
 <translation-unit>     ::= (<ows> <external-declaration> <ows> (<end-of-statement> | <end-of-file>))*
 
-<external-declaration> ::= <function-definition> | <variable-definition>
+(* Translation Unit *)
+<external-declaration> ::= <common-statement> | <function-definition>
 
 (* Variables *)
-<variable-definition>  ::= <variable-qualifier> <ws> <variable-name> <ows> ':' <ows> <type> (<ows> <assign-operator> <ows> <expression>)?
+<variable-definition>  ::= <variable-qualifier> <ws> <variable-name> <ows> ':' <ows> <type> (<ows> <assignment-operator> <ows> <expression>)?
 <variable-qualifier>   ::= 'var'
                          | 'const'
 <variable-name>        ::= <identifier>
@@ -38,17 +39,18 @@ language.
 <function-parameters> ::= '(' <ows> ')'
 <return-type>         ::= <type>
 <function-body>       ::= <block>
+<block>               ::= '{' <ows> <statement> <ows> (<end-of-statement> <ows> <statement> <ows>)* <end-of-statement>? <ows> '}'
+<statement>           ::= <common-statement> | <return-statement>
+<return-statement>    ::= 'return' <ws> <expression>
 
 (* Statements *)
-<block>               ::= '{' <ows> <statement> <ows> (<end-of-statement> <ows> <statement> <ows>)* <end-of-statement>? <ows> '}'
 <end-of-statement>    ::= ';' | <line-break>
-<statement>           ::= <return-statement> | <variable-definition> | <assign-expression>
-<return-statement>    ::= 'return' <ws> <expression>
+<common-statement>    ::= <variable-definition> | <assignment-expression>
 
 (* Expressions *)
-<expression>          ::= <integer> | <identifier>
-<assign-expression>   ::= <variable-name> <ows> <assign-operator> <ows> <expression>
-<assign-operator>     ::= '='
+<expression>            ::= <integer-literal> | <variable-name>
+<assignment-expression> ::= <variable-name> <ows> <assignment-operator> <ows> <expression>
+<assignment-operator> ::= '='
                         | '*='
                         | '/='
                         | '%='
@@ -65,7 +67,7 @@ language.
 <identifier>          ::= (<alpha> | '_') (<alpha> | <digit> | '_')*
 
 (* Literals *)
-<integer>             ::= <integer-base10> | <integer-base16>
+<integer-literal>     ::= <integer-base10> | <integer-base16>
 <integer-base10>      ::= #'[1-9]' (<digit> | '_')* | '0'
 <integer-base16>      ::= #'0[Xx]' <hex-digit> (<hex-digit> | '_')*
 
-- 
2.44.0

Re: [PATCH 1/4] docs: spec: refactor grammar specification

[Johnny Richard]

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

[PATCH 2/4] docs: spec: immediate constant initialization

[ricardo_kagawa]

From: Ricardo Kagawa <ricardo_kagawa@disroot.org>

This commit prevents declarations of uninitialized constants, as well as
prevents the use of assignment operators in variable and constant
declarations. This change was originally suggested by Maniero, with
different non-terminal names.

Signed-off-by: Ricardo Kagawa <ricardo_kagawa@disroot.org>
---
 docs/pages/language-specification.md | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs/pages/language-specification.md b/docs/pages/language-specification.md
index 9f4383d..8d8544a 100644
--- a/docs/pages/language-specification.md
+++ b/docs/pages/language-specification.md
@@ -28,10 +28,10 @@ language.
 <external-declaration> ::= <common-statement> | <function-definition>
 
 (* Variables *)
-<variable-definition>  ::= <variable-qualifier> <ws> <variable-name> <ows> ':' <ows> <type> (<ows> <assignment-operator> <ows> <expression>)?
-<variable-qualifier>   ::= 'var'
-                         | 'const'
-<variable-name>        ::= <identifier>
+<variable-definition>   ::= 'var' <ws> <variable-name> <ows> ':' <ows> <type> <ows> <variable-initializer>?
+<constant-definition>   ::= 'const' <ws> <variable-name> <ows> ':' <ows> <type> <ows> <variable-initializer>
+<variable-name>         ::= <identifier>
+<variable-initializer>  ::= '=' <ows> <expression>
 
 (* Functions *)
 <function-definition> ::= 'fn' <ws> <function-name> <ows> <function-parameters> <ows> ':' <ows> <return-type> <ows> <function-body>
-- 
2.44.0

Re: [PATCH 2/4] docs: spec: immediate constant initialization

[Johnny Richard]

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

[PATCH 3/4] docs: spec: remove assignment as expression

[ricardo_kagawa]

From: Ricardo Kagawa <ricardo_kagawa@disroot.org>

This commit prevents the use of assignments as expressions, to prevent
chained assignments and the use of assignments inside potential future
 `if`, `while` and other statements. However, assignments are still
valid statements.

Signed-off-by: Ricardo Kagawa <ricardo_kagawa@disroot.org>
---
 docs/pages/language-specification.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/docs/pages/language-specification.md b/docs/pages/language-specification.md
index 8d8544a..724ed67 100644
--- a/docs/pages/language-specification.md
+++ b/docs/pages/language-specification.md
@@ -45,11 +45,8 @@ language.
 
 (* Statements *)
 <end-of-statement>    ::= ';' | <line-break>
-<common-statement>    ::= <variable-definition> | <assignment-expression>
-
-(* Expressions *)
-<expression>            ::= <integer-literal> | <variable-name>
-<assignment-expression> ::= <variable-name> <ows> <assignment-operator> <ows> <expression>
+<common-statement>    ::= <variable-definition> | <constant-definition> | <assignment>
+<assignment>          ::= <variable-name> <ows> <assignment-operator> <ows> <expression>
 <assignment-operator> ::= '='
                         | '*='
                         | '/='
@@ -62,6 +59,9 @@ language.
                         | '^='
                         | '|='
 
+(* Expressions *)
+<expression>          ::= <integer-literal> | <variable-name>
+
 (* Identifiers *)
 <type>                ::= 'u32'
 <identifier>          ::= (<alpha> | '_') (<alpha> | <digit> | '_')*
-- 
2.44.0

Re: [PATCH 3/4] docs: spec: remove assignment as expression

[Johnny Richard]

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

[PATCH 4/4] docs: spec: postpone assignment operators

[ricardo_kagawa]

From: Ricardo Kagawa <ricardo_kagawa@disroot.org>

This commit temporarily removes the definition of assignment operators
from the grammar, since their corresponding binary operators are still
not in the grammar. The incomplete grammar would be ill defined,
although still syntactically valid.

Signed-off-by: Ricardo Kagawa <ricardo_kagawa@disroot.org>
---
 docs/pages/language-specification.md | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/docs/pages/language-specification.md b/docs/pages/language-specification.md
index 724ed67..3cf050e 100644
--- a/docs/pages/language-specification.md
+++ b/docs/pages/language-specification.md
@@ -48,16 +48,6 @@ language.
 <common-statement>    ::= <variable-definition> | <constant-definition> | <assignment>
 <assignment>          ::= <variable-name> <ows> <assignment-operator> <ows> <expression>
 <assignment-operator> ::= '='
-                        | '*='
-                        | '/='
-                        | '%='
-                        | '+='
-                        | '-='
-                        | '<<='
-                        | '>>='
-                        | '&='
-                        | '^='
-                        | '|='
 
 (* Expressions *)
 <expression>          ::= <integer-literal> | <variable-name>
-- 
2.44.0

Re: [PATCH 4/4] docs: spec: postpone assignment operators

[Johnny Richard]

Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

Re: [PATCH 0/4] docs: spec: constant initialization and assignments

[Carlos Maniero]

Thank you so much for your contribution, Ricardo!

Just a few observations:

- In the future patches don't forget to define the
  *format.subjectPrefix = PATCH olang*, this is how the olang CI is
  triggered. This can be configured once at the repo's *.git/config*.
- We reword your first patch to "docs: spec: make non-terminals more
  descriptivedocs: spec: make non-terminals more descriptive" just to
  make clear at the short commit message, what the actual change is.
  There is a concept we are trying to follow called git recipe history
  [1].

Other than that everything is completely amazing! We are glad to
receive your inputs.

Applied!

To git.sr.ht:~johnnyrichard/olang
   7cd840e..0046920  main -> main