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Pre: add an interpose macro for SQL output.

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Richard Newman 2017-03-07 10:31:28 -08:00
parent 7bcf311db9
commit 1961815acd
1 changed files with 19 additions and 12 deletions
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31
query-sql/src/lib.rs
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@ -172,6 +172,19 @@ impl QueryFragment for Op {
}
}
macro_rules! interpose {
( $name: ident, $across: expr, $body: block, $inter: block ) => {
let mut seq = $across.iter();
if let Some($name) = seq.next() {
$body;
for $name in seq {
$inter;
$body;
}
}
}
}
impl QueryFragment for Constraint {
fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult {
use self::Constraint::*;
@ -208,12 +221,9 @@ impl QueryFragment for TableList {
return Ok(());
}
source_alias_push_sql(out, &self.0[0])?;
for sa in self.0.iter().skip(1) {
out.push_sql(", ");
source_alias_push_sql(out, sa)?;
}
interpose!(sa, self.0,
{ source_alias_push_sql(out, sa)? },
{ out.push_sql(", ") });
Ok(())
}
}
@ -258,12 +268,9 @@ impl QueryFragment for SelectQuery {
}
out.push_sql(" WHERE ");
self.constraints[0].push_sql(out)?;
for constraint in self.constraints[1..].iter() {
out.push_sql(" AND ");
constraint.push_sql(out)?;
}
interpose!(constraint, self.constraints,
{ constraint.push_sql(out)? },
{ out.push_sql(" AND ") });
// Guaranteed to be positive: u64.
if let Some(limit) = self.limit {