Fluid Template Variable Parsing Error with Spaces around Operators

[garvinhicking]

From: https://forge.typo3.org/issues/104363

h2. Steps to Reproduce:

Use the following Fluid template code:

testVar: {testVar} 

A: {testVar - 1} 

B: {testVar - 1 } 

C: {testVar-1} 

D: {testVar + 1} 

E: {testVar + 1 } 

F: {testVar+1} 

Set testVar to any integer, e.g., 2.

h3. Expected Output:

testVar: 2
A: 1
B: 1
C: 1
D: 3
E: 3
F: 3

h3. Actual Output:

testVar: 2
A: 1
B: {testVar - 1 }
C:
D: 3
E: {testVar + 1 }
F: 3

h2. Analysis:

• The expression {testVar - 1} and {testVar + 1} are parsed correctly when there are spaces around the operator.
• {testVar - 1 } and {testVar + 1 } result in no evaluation and return the expression as a string.
• {testVar+1} without space is parsed and evaluated correctly.
• {testVar-1} without space is not parsed and evaluated correctly.

[s2b]

Case C isn't and won't be supported because testVar-1 is treated as a variable identifier. This is especially useful for array keys properties:

{myVar.my-array-key.test}

The leading/trailing whitespace are addressed with the attached PR.