fixes

Author: VoxSciurorum

src/doc/reference/opencilk-language-reference.md

@@ -61,23 +61,24 @@ identifiers.
 A statement using `cilk_spawn` is the start of a potentially parallel
 region of code.
 
-The `cilk_spawn` keyword should appear at the start of an expression
-statement or after the `=` sign of an assignment (or `+=`, `-=`,
-etc.).
+The `cilk_spawn` keyword should appear before an expression statement,
+block statement, or after the `=` sign of an assignment.
 
 ```cilkc
 int x = cilk_spawn f(i++);
 cilk_spawn y[j++] = f(i++);
 cilk_spawn { z[j++] = f(i++); }
 ```
 
-Although the compiler accepts `cilk_spawn` before almost any
+Other statements, other than declarations, may also be spawned.
+Although the compiler also accepts `cilk_spawn` before almost any
 expression, spawns inside of expressions are unlikely to have the
-expected semantics.  A future version of the language may explicitly
-limit `cilk_spawn` to the contexts above, at or near the top of the
-parse tree of a statement.
+expected semantics.  A future version of the language may require
+`cilk_spawn` to precede an expression statement, block statement, or
+right hand sign of an assignment that is the entire body of an
+expression statement.
 
-A declaration may not begin with `cilk_spawn`.
+[The compiler also accepts `cilk_spawn;`.]
 
 ### Sync
 
@@ -113,6 +114,8 @@ cilk_scope {
 // x, y, and z are usable here because of the implicit sync
 ```
 
+[The compiler also accepts `cilk_scope;`.]
+
 ### For
 
 A loop written using `cilk_for` executes each iteration of its body in
@@ -127,8 +130,8 @@ cilk_for (int i = 0; i < n; ++i)
 
 The syntax of a `cilk_for` statement is very similar to a C `for`
 statement except that none of the three items in parentheses may be
-omitted.  Parallel C++ range `for` constructs are not supported in
-OpenCilk 2.0.
+omitted.  C++ range `for` constructs are not supported with `cilk_for`
+in OpenCilk 2.0.
 
 The first statement inside parentheses must declare at least one
 variable.
@@ -176,9 +179,6 @@ can be manually overridden with a pragma:
 The pragma in the example tells the compiler that each group of 128
 consecutive iterations should be executed as a serial loop.  If there
 are 1024 loop iterations in total, there are only 8 parallel tasks.
-There is guaranteed to be no spawn or sync between the iterations
-for `i=0` and `i=1` (assuming `n` is at least 2, otherwise there
-will be no second iteration).
 
 In OpenCilk 2.0 the argument to the grain size pragma must be an
 integer constant in the range 1..2<sup>31</sup>-1.
@@ -217,11 +217,11 @@ In the current version of OpenCilk the callbacks may be omitted in
 contexts other than definition of a variable.  This behavior may be
 removed in a future version of OpenCilk.
 
-In the current version of OpenCilk the arguments to `cilk_reducer`
-are evaluated each time a reducer is created.  This behavior may
-change in a future version of OpenCilk.  For compatibility and
-predictable behavior the arguments to `cilk_reducer` should not
-have side effects.
+In the current version of OpenCilk the arguments to `cilk_reducer` are
+evaluated each time a reducer is created but not when a reducer is
+accessed.  This behavior may change in a future version of OpenCilk.
+For compatibility and predictable behavior the arguments to
+`cilk_reducer` should not have side effects.
 
 ## Execution of an OpenCilk program
 
@@ -394,7 +394,7 @@ series with the continuation of the spawn.
 
 ### Loops
 
-Writing `cilk_for` instead of `for` causes the loop to be rewritten
+Writing `cilk_for` instead of `for` may cause the loop to be rewritten
 into a loop over an integer range determined before the first
 iteration.