put block docs in a reusable string

Author: baggepinnen

src/uncertainty_interface.jl

@@ -522,16 +522,18 @@ function IntervalArithmetic.Interval(d::δ{C}) where C <: Complex
     Complex(re, im)
 end
 
-
+const _blockdocs = """
+- `[-N, 0]` denotes a repeated real block of size `N`
+- `[N, 0]` denotes a repeated complex block of size `N`
+- `[ny, nu]` denotes a full complex block of size `ny × nu`
+"""
 
 """
     block_structure(Δ)
 
 Take a vector of uncertain elements and return a vector of vectors with the block
 structure of perturbation blocks as described by μ-tools, i.e.
-- `[-N, 0]` denotes a repeated real block of size `N`
-- `[N, 0]` denotes a repeated complex block of size `N`
-- `[ny, nu]` denotes a full complex block of size `ny × nu`
+$_blockdocs
 """
 function block_structure(D)
     perm = sortperm(D, by=d->d.name)
@@ -572,9 +574,7 @@ end
 Returns the block structure of `P.Δ` as well as `P.M` permuted according to the sorted block structure.
 `blocks` is a vector of vectors with the block
 structure of perturbation blocks as described by μ-tools, i.e.
-- `[-N, 0]` denotes a repeated real block of size `N`
-- `[N, 0]` denotes a repeated complex block of size `N`
-- `[ny, nu]` denotes a full complex block of size `ny × nu`
+$_blockdocs
 """
 function blocksort(P::UncertainSS)
     blocks, perm = block_structure(P.Δ)