summaryrefslogtreecommitdiffstats
path: root/doc/ParseCmd.3
diff options
context:
space:
mode:
Diffstat (limited to 'doc/ParseCmd.3')
-rw-r--r--doc/ParseCmd.345
1 files changed, 24 insertions, 21 deletions
diff --git a/doc/ParseCmd.3 b/doc/ParseCmd.3
index b5fc6d0..f3b3aeb 100644
--- a/doc/ParseCmd.3
+++ b/doc/ParseCmd.3
@@ -80,7 +80,6 @@ if the parse was successful.
Points to structure that was filled in by a previous call to
\fBTcl_ParseCommand\fR, \fBTcl_ParseExpr\fR, \fBTcl_ParseVarName\fR, etc.
.BE
-
.SH DESCRIPTION
.PP
These procedures parse Tcl commands or portions of Tcl commands such as
@@ -202,30 +201,30 @@ If an error or other exception occurs while evaluating the tokens
(such as a reference to a non-existent variable) then the return value
is NULL and an error message is left in \fIinterp\fR's result. The use
of \fBTcl_EvalTokens\fR is deprecated.
-
.SH "TCL_PARSE STRUCTURE"
.PP
\fBTcl_ParseCommand\fR, \fBTcl_ParseExpr\fR, \fBTcl_ParseBraces\fR,
\fBTcl_ParseQuotedString\fR, and \fBTcl_ParseVarName\fR
return parse information in two data structures, Tcl_Parse and Tcl_Token:
+.PP
.CS
typedef struct Tcl_Parse {
- const char *\fIcommentStart\fR;
- int \fIcommentSize\fR;
- const char *\fIcommandStart\fR;
- int \fIcommandSize\fR;
- int \fInumWords\fR;
- Tcl_Token *\fItokenPtr\fR;
- int \fInumTokens\fR;
- ...
-} Tcl_Parse;
+ const char *\fIcommentStart\fR;
+ int \fIcommentSize\fR;
+ const char *\fIcommandStart\fR;
+ int \fIcommandSize\fR;
+ int \fInumWords\fR;
+ Tcl_Token *\fItokenPtr\fR;
+ int \fInumTokens\fR;
+ ...
+} \fBTcl_Parse\fR;
typedef struct Tcl_Token {
- int \fItype\fR;
- const char *\fIstart\fR;
- int \fIsize\fR;
- int \fInumComponents\fR;
-} Tcl_Token;
+ int \fItype\fR;
+ const char *\fIstart\fR;
+ int \fIsize\fR;
+ int \fInumComponents\fR;
+} \fBTcl_Token\fR;
.CE
.PP
The first five fields of a Tcl_Parse structure
@@ -267,6 +266,7 @@ the \fInumComponents\fR field describes how many of these there are.
The \fItype\fR field has one of the following values:
.TP 20
\fBTCL_TOKEN_WORD\fR
+.
This token ordinarily describes one word of a command
but it may also describe a quoted or braced string in an expression.
The token describes a component of the script that is
@@ -281,29 +281,32 @@ number of sub-tokens that make up the word, including sub-tokens
of \fBTCL_TOKEN_VARIABLE\fR and \fBTCL_TOKEN_BS\fR tokens.
.TP
\fBTCL_TOKEN_SIMPLE_WORD\fR
+.
This token has the same meaning as \fBTCL_TOKEN_WORD\fR, except that
the word is guaranteed to consist of a single \fBTCL_TOKEN_TEXT\fR
sub-token. The \fInumComponents\fR field is always 1.
.TP
\fBTCL_TOKEN_EXPAND_WORD\fR
-.VS 8.5
+.
This token has the same meaning as \fBTCL_TOKEN_WORD\fR, except that
the command parser notes this word began with the expansion
prefix \fB{*}\fR, indicating that after substitution,
the list value of this word should be expanded to form multiple
arguments in command evaluation. This
token type can only be created by Tcl_ParseCommand.
-.VE 8.5
.TP
\fBTCL_TOKEN_TEXT\fR
+.
The token describes a range of literal text that is part of a word.
The \fInumComponents\fR field is always 0.
.TP
\fBTCL_TOKEN_BS\fR
+.
The token describes a backslash sequence such as \fB\en\fR or \fB\e0xa3\fR.
The \fInumComponents\fR field is always 0.
.TP
\fBTCL_TOKEN_COMMAND\fR
+.
The token describes a command whose result must be substituted into
the word. The token includes the square brackets that surround the
command. The \fInumComponents\fR field is always 0 (the nested command
@@ -311,6 +314,7 @@ is not parsed; call \fBTcl_ParseCommand\fR recursively if you want to
see its tokens).
.TP
\fBTCL_TOKEN_VARIABLE\fR
+.
The token describes a variable substitution, including the
\fB$\fR, variable name, and array index (if there is one) up through the
close parenthesis that terminates the index. This token is followed
@@ -326,6 +330,7 @@ array index. The \fInumComponents\fR field includes nested sub-tokens
that are part of \fBTCL_TOKEN_VARIABLE\fR tokens in the array index.
.TP
\fBTCL_TOKEN_SUB_EXPR\fR
+.
The token describes one subexpression of an expression
(or an entire expression).
A subexpression may consist of a value
@@ -352,6 +357,7 @@ counts the total number of sub-tokens that make up the subexpression;
this includes the sub-tokens for any nested \fBTCL_TOKEN_SUB_EXPR\fR tokens.
.TP
\fBTCL_TOKEN_OPERATOR\fR
+.
The token describes one operator of an expression
such as \fB&&\fR or \fBhypot\fR.
A \fBTCL_TOKEN_OPERATOR\fR token is always preceded by a
@@ -383,7 +389,6 @@ is always 0.
After \fBTcl_ParseCommand\fR returns, the first token pointed to by
the \fItokenPtr\fR field of the
Tcl_Parse structure always has type \fBTCL_TOKEN_WORD\fR or
-.VS 8.5
\fBTCL_TOKEN_SIMPLE_WORD\fR or \fBTCL_TOKEN_EXPAND_WORD\fR.
It is followed by the sub-tokens
that must be concatenated to produce the value of that word.
@@ -392,7 +397,6 @@ of \fBTCL_TOKEN_EXPAND_WORD\fR token for the second word,
followed by sub-tokens for that
word, and so on until all \fInumWords\fR have been accounted
for.
-.VE 8.5
.PP
After \fBTcl_ParseExpr\fR returns, the first token pointed to by
the \fItokenPtr\fR field of the
@@ -459,6 +463,5 @@ There are additional fields in the Tcl_Parse structure after the
\fBTcl_ParseCommand\fR, \fBTcl_ParseExpr\fR, \fBTcl_ParseBraces\fR,
\fBTcl_ParseQuotedString\fR, and \fBTcl_ParseVarName\fR; they should not be
referenced by code outside of these procedures.
-
.SH KEYWORDS
backslash substitution, braces, command, expression, parse, token, variable substitution