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Merge branch 'master' of https://github.com/eskimor/misc-stuff-including-D-programming-language-web-stuff

This commit is contained in:
Adam D. Ruppe 2013-01-11 10:19:01 -05:00
parent 2acfaa8a28 35f0ac97fd
commit ed42fbf662
1 changed files with 25 additions and 22 deletions
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47
querygenerator.d
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@ -117,7 +117,7 @@ string createQueryGenerator(string preSql) {
* data_ will be made available with D's 'with' statement to the embedded code in queryString. So you can access the elements just as regular variables.
*
* Params:
* queryString = An SQL template. An SQL consists of nested blocks. The
* queryString = An SQL template. An SQL template consists of nested blocks. The
* uppermost block is the queryString itself, you create subblocks by
* enclosing it in braces '{}'.
@ -150,14 +150,14 @@ string createQueryGenerator(string preSql) {
might access the loop variable, ('a' in our case).
Multiple declarations of the form '${}' might be present
within the declaration part, they may be separated with
within the declaration part, they may be separated by
white space.
__Body part__
If no declaration part is present, then the whole content
of the block is the body part. (This is if the first
character is no '$'.) Otherwise it starts with the colon
of the block is the body part. (This is, if the first
character is no '$'.) Otherwise it starts after the colon
at the end of the declaration part.
Everything in the body part will be echoed to the
@ -172,7 +172,7 @@ string createQueryGenerator(string preSql) {
3. A '$' will trigger an error as it is only valid in the
declaration part.
4. SQL string which can either start with " or with ' it
4. SQL string which can either start with " or with '. It
might contain any of '{' '}' '$' '#' they all will be
ignored within a string. Apart from this, no escaping of
these characters is possible at the moment.
@ -197,8 +197,7 @@ string createQueryGenerator(string preSql) {
.. params[n], all declarations made in the declarations
parts of the blocks above it and the contents of the data_ struct.
It is made available with D's 'with' statement so
data_.foo will just be
'foo'.
data_.foo will just be 'foo'.
__Blocks__
@ -206,19 +205,24 @@ string createQueryGenerator(string preSql) {
expression. If a block contains a D expression or a
subblock which contains D expressions, then its contents
will only be included in the output if at least one of
the D expressions are valid. (Different from their init
value). So if you have a SQL expression of the
the D expressions are valid or if it contains a text only sub block.
So if you have a SQL expression of the
form {someColumn=#{some D code}} there will be no output
at all if #{some D code} was not valid. If a block does
not contain any D code and neither do any sub blocks then
its output will be included in the output, of the
containing block. Which in turn will only be emitted if
this block either has no D expressions at all or at least
on of the is valid.
its output will be included in the output of the
containing block. If you want to ensure that a particular
text does not get dropped, include it in its own block.
The second property that makes blocks useful is that if a block produces no output, for the above mentioned reasons, then the text before it will be dropped
if there were D expression found already. It will also be dropped if the preceding block vanished. This way you can concatenate blocks with ' and ' and ' or '
and they will be dropped if not applicable. A leading ' where ' on the other hand would not be dropped in any case, except the whole output vanishes.
The second property that makes blocks useful is that if a
block produces no output, for the above mentioned
reasons, then the text before it will be dropped if there
were no valid sub blocks found already in the parent block.
It will also be dropped if the preceding block vanished. This way you can
concatenate blocks with ' and ' and ' or ' and they will
be dropped if not applicable. A leading ' where ' on the
other hand would not be dropped in any case, except the
whole output vanishes.
For examples, see the unittests, a more complex example, I used in reality is here:
`({${db=params[0]} : `
@ -236,11 +240,11 @@ string createQueryGenerator(string preSql) {
comes from the data_ struct) followed by an inner
variable declaration of arData, you can see both d (the
looping variable) and db from the outer block are
accessible. Afterwards the body starts, which starts with a
block containing '(' and subblocks of a comparisons with a D
accessible. Afterwards the body starts with a
block containing '(' and subblocks of comparisons with a D
expression like {({date>=#{d.from}})}.
If all D expressions in the block like d.from evaluate to
an empty string, the whole containig block will not produce
an empty string, the whole containing block will not produce
any output. So not even '()' this is because they are
enclused in a subblock. The 'and' between {date>=#{d.from}}
and {date<=#{d.to}} for example will only appear in the
@ -248,7 +252,7 @@ string createQueryGenerator(string preSql) {
string.
The outputs of each loop iteration will be separated with " or " by default,
you can change this by setting queryGenSep in the declaration part.
you can change this, by setting queryGenSep in the declaration part.
*/
CreatedQuery createQuery(string queryString, StructT, Params...)(StructT data_, Params params) {
@ -503,9 +507,8 @@ string preSqlParser(ref string data, int level=0) {
out_cmd~="if("~wasValid~"==0 && "~validCount~">0) {\n"; // validCount has to be greater than 0 otherwise we have removed the data already. (See above)
out_cmd~=buf~"="~buf~"[0..$-"~text~".length];\n}\n";
out_cmd~="if("~wasValid~">0 || "~wasValid~"==0) {\n";
out_cmd~=wasValid~"="~wasValid~"==-1 ? 1 : "~wasValid~";\n";
out_cmd~=validCount~"="~validCount~"==-1 ? "~wasValid~" : "~validCount~"+"~wasValid~";\n";
out_cmd~="}\n";
break;
case '}' :
goto finish;