Despite the emphasis on securities rather than on cash streams in general financialtheories, the concept of cash stream remains useful in modelling realistic financial decision problems.The paper presents a unified view on cash stream modelling, valid in both continuous and discretetime, in the standard analytical framework of Schwartz distributions. Abstract cash stream spacesare defined by stipulating certain general properties, and are then identified as some well-knownLebesgue lattices of measures on the real line. All basic financial notions such as discounting orpreference ordering carry over to the general case, and the linear decision problems become instancesof infinite-dimensional linear programming.