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authordgp <dgp@users.sourceforge.net>2013-07-02 10:36:32 (GMT)
committerdgp <dgp@users.sourceforge.net>2013-07-02 10:36:32 (GMT)
commit5599b1864958a90b4754b554eadb41722bdc9246 (patch)
treea02a107528a2fdfa0050e4ec13238cbccb65721c /generic/tclCompile.c
parent5d46ba8b3ec614cfb931011d5b6c35d9eb046d75 (diff)
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comment improvements
Diffstat (limited to 'generic/tclCompile.c')
-rw-r--r--generic/tclCompile.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 6f5ef50..05daabf 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -1764,6 +1764,7 @@ CompileCommandTokens(
assert (numWords > 0);
+ /* Determine whether any words of the command require expansion */
for (wordIdx = 0; wordIdx < numWords;
wordIdx++, tokenPtr += tokenPtr->numComponents + 1) {
if (tokenPtr->type == TCL_TOKEN_EXPAND_WORD) {
@@ -1772,6 +1773,7 @@ CompileCommandTokens(
}
}
+ /* Do we know the command word? */
Tcl_IncrRefCount(cmdObj);
tokenPtr = parsePtr->tokenPtr;
cmdKnown = TclWordKnownAtCompileTime(tokenPtr, cmdObj);
@@ -1791,6 +1793,7 @@ CompileCommandTokens(
}
}
}
+ /* If cmdPtr != NULL, we will try to call cmdPtr->compileProc */
/* Pre-Compile */
@@ -2112,7 +2115,22 @@ TclCompileScript(
p = next;
if (parse.numWords == 0) {
- /* TODO: Document justification */
+ /*
+ * The "command" parsed has no words. In this case
+ * we can skip the rest of the loop body. With no words,
+ * clearly CompileCommandTokens() has nothing to do. Since
+ * the parser aggressively sucks up leading comment and white
+ * space, including newlines, parse.commandStart must be
+ * pointing at either the end of script, or a command-terminating
+ * semi-colon. In either case, the TclAdvance*() calls have
+ * nothing to do. Finally, when no words are parsed, no
+ * tokens have been allocated at parse.tokenPtr so there's
+ * also nothing for Tcl_FreeParse() to do.
+ *
+ * The advantage of this shortcut is that CompileCommandTokens()
+ * can be written with an assumption that parse.numWords > 0,
+ * with the implication the CCT() always generates bytecode.
+ */
continue;
}
@@ -2145,7 +2163,7 @@ TclCompileScript(
* command is thrown away before moving on to the next command).
* For the last command compiled, we need to undo that INST_POP
* so that the result of the last command becomes the result of
- * the script. These code here removes that trailing INST_POP.
+ * the script. The code here removes that trailing INST_POP.
*/
envPtr->cmdMapPtr[lastCmdIdx].numCodeBytes--;
envPtr->codeNext--;