curl/var: change byte offset syntax for assignments

Follow-up to 40c264db61 after discussions on IRC.

The new style is

  name[0-99]=contents

and

  name[0-99]@filename

A) This does not cause the same problems with old curl versions trying
the new syntax as this way will cause old curls just fail with syntax
error and not risk using the wrong file.

B) Adds the same byte range support for "normal" assigns, which the
previous syntax did not. Thus lets a user get a partial content of a
variable etc.

Added test 790 and 791 to verify non-file assigns with ranges.

Closes #15862

tests/data/Makefile.am

@@ -110,7 +110,7 @@ test727 test728 test729 test730 test731 test732 test733 test734 test735 \
 test736 test737 test738 test739 test740 test741 test742 \
 \
 test780 test781 test782 test783 test784 test785 test786 test787 test788 \
-test789 \
+test789 test790 test791 \
 \
 test799 test800 test801 test802 test803 test804 test805 test806 test807 \
 test808 test809 test810 test811 test812 test813 test814 test815 test816 \

tests/data/test784

@@ -35,7 +35,7 @@ http
 --variable with a file byte range
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@%LOGDIR/in%TESTNUMBER;[5-15]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[5-15]@%LOGDIR/in%TESTNUMBER" --expand-data '{{name}}'
 </command>
 <file name="%LOGDIR/in%TESTNUMBER">
 On the first Monday of the month of April, 1625, the market town of Meung

tests/data/test785

@@ -35,7 +35,7 @@ http
 --variable with a file byte range without end
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@%LOGDIR/in%TESTNUMBER;[5-]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[5-]@%LOGDIR/in%TESTNUMBER" --expand-data '{{name}}'
 </command>
 <file name="%LOGDIR/in%TESTNUMBER">
 On the first Monday of the month of April, 1625, the market town of Meung

tests/data/test786

@@ -35,7 +35,7 @@ http
 --variable with a file byte range, reading from stdin
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@-;[5-15]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[5-15]@-" --expand-data '{{name}}'
 </command>
 <stdin>
 On the first Monday of the month of April, 1625, the market town of Meung

tests/data/test787

@@ -21,7 +21,7 @@ http
 --variable with a file byte range, bad range
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@&LOGDIR/fooo;[15-14]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[15-14]@&LOGDIR/fooo" --expand-data '{{name}}'
 </command>
 </client>
 

tests/data/test788

@@ -35,7 +35,7 @@ http
 --variable with a file and single-byte byte range
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@%LOGDIR/in%TESTNUMBER;[15-15]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[15-15]@%LOGDIR/in%TESTNUMBER" --expand-data '{{name}}'
 </command>
 <file name="%LOGDIR/in%TESTNUMBER">
 On the first Monday of the month of April, 1625, the market town of Meung

tests/data/test789

@@ -35,7 +35,7 @@ http
 --variable with a file and byte range out of file
 </name>
 <command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable name"@%LOGDIR/in%TESTNUMBER;[75-85]" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[75-85]@%LOGDIR/in%TESTNUMBER" --expand-data '{{name}}'
 </command>
 <file name="%LOGDIR/in%TESTNUMBER">
 On the first Monday of the month of April, 1625, the market town of Meung

tests/data/test790

@@ -0,0 +1,56 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+--variable
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data crlf="yes">
+HTTP/1.1 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<name>
+--variable with a byte range using plain assign
+</name>
+<command>
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[5-9]=0123456789abcdef" --expand-data '{{name}}'
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes" nonewline="yes">
+POST /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+Content-Length: 5
+Content-Type: application/x-www-form-urlencoded
+
+56789
+</protocol>
+</verify>
+</testcase>

tests/data/test791

@@ -0,0 +1,56 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+--variable
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data crlf="yes">
+HTTP/1.1 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<name>
+--variable with a byte range using plain assign, out of range
+</name>
+<command>
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[10-30]=0123456789abcdef" --expand-data '{{name}}'
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes" nonewline="yes">
+POST /%TESTNUMBER HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+Content-Length: 6
+Content-Type: application/x-www-form-urlencoded
+
+abcdef
+</protocol>
+</verify>
+</testcase>