fix printing of arrays of affine expressions (#123)

* fix printing of arrays of affine expressions

* bumped patch version

Author: lucaferranti

Project.toml

@@ -1,7 +1,7 @@
 name = "IntervalLinearAlgebra"
 uuid = "92cbe1ac-9c24-436b-b0c9-5f7317aedcd5"
 authors = ["Luca Ferranti"]
-version = "0.1.4"
+version = "0.1.5"
 
 [deps]
 CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"

src/pils/affine_expressions.jl

@@ -88,30 +88,38 @@ end
 
 (ae::AffineExpression)(p::Vector{<:Number}) = dot(ae.coeffs[1:end-1], p) + ae.coeffs[end]
 
-## printing
-function _tostring(ae::AffineExpression)
-    iszero(ae.coeffs) && return "0"
-    str = ""
-    @inbounds for (i, x) in enumerate(_vars_dict[:vars])
-        c = ae.coeffs[i]
-        iszero(c) && continue
-        sgn = c > 0 ? "+" : "-"
-        c = abs(c) == 1 ? "" : "$(abs(c))"
-        str *= sgn * c * "$(x)"
-    end
-
-    c = last(ae.coeffs)
-    if !iszero(c)
-        sgn = c > 0 ? "+" : ""
-        str *= sgn * "$(c)"
+function show(io::IO, ae::AffineExpression)
+    first_printed = false
+    if iszero(ae.coeffs)
+        print(io, 0)
+    else
+        @inbounds for (i, x) in enumerate(_vars_dict[:vars])
+            c = ae.coeffs[i]
+            iszero(c) && continue
+            if c > 0
+                if first_printed
+                    print(io, "+")
+                end
+            else
+                print(io, "-")
+            end
+            if abs(c) != 1
+                print(io, abs(c))
+            end
+            print(io, x)
+            first_printed = true
+        end
+
+        c = last(ae.coeffs)
+        if !iszero(c)
+            if c > 0 && first_printed
+                print(io, "+")
+            end
+            print(io, c)
+        end
     end
-    str = (str[1] == '+' ? str[2:end] : str)
-    return str
 end
 
-show(io::IO, ae::AffineExpression) = print(io, _tostring(ae))
-
-
 #########################
 # BASIC FUNCTIONS       #
 #########################

test/test_pils/test_linexpr.jl

@@ -25,11 +25,10 @@ end
     @affinevars x y z
 
     p1 = x - y + 3z
-    @test IntervalLinearAlgebra._tostring(p1) == "x-y+3z"
+    @test string(p1) == "x-y+3z"
     p2 = y + x - z - 2
-    @test IntervalLinearAlgebra._tostring(p2) == "x+y-z-2"
-    @test IntervalLinearAlgebra._tostring(p1 - p1) == "0"
-
+    @test string(p2) == "x+y-z-2"
+    @test string(p1 - p1) == "0"
     @test +p1 == p1
     @test -p1 == -x + y - 3z
     @test p2([1, 1, 1]) == -1